diff --git a/lib/analyze-action-post.js b/lib/analyze-action-post.js
index b30ab9f097..323549b8b1 100644
--- a/lib/analyze-action-post.js
+++ b/lib/analyze-action-post.js
@@ -119928,6 +119928,11 @@ var featureConfig = {
     legacyApi: true,
     minimumVersion: "2.15.0"
   },
+  ["csharp_cache_bmn" /* CsharpCacheBuildModeNone */]: {
+    defaultValue: false,
+    envVar: "CODEQL_ACTION_CSHARP_CACHE_BMN",
+    minimumVersion: void 0
+  },
   ["csharp_new_cache_key" /* CsharpNewCacheKey */]: {
     defaultValue: false,
     envVar: "CODEQL_ACTION_CSHARP_NEW_CACHE_KEY",
@@ -120763,6 +120768,9 @@ var glob = __toESM(require_glob3());
 function getJavaTempDependencyDir() {
   return (0, import_path.join)(getTemporaryDirectory(), "codeql_java", "repository");
 }
+function getCsharpTempDependencyDir() {
+  return (0, import_path.join)(getTemporaryDirectory(), "codeql_csharp", "repository");
+}
 
 // src/debug-artifacts.ts
 function sanitizeArtifactName(name) {
@@ -120883,14 +120891,19 @@ async function runWrapper() {
         );
       }
     }
-    const javaTempDependencyDir = getJavaTempDependencyDir();
-    if (fs6.existsSync(javaTempDependencyDir)) {
-      try {
-        fs6.rmSync(javaTempDependencyDir, { recursive: true });
-      } catch (error4) {
-        logger.info(
-          `Failed to remove temporary Java dependencies directory: ${getErrorMessage(error4)}`
-        );
+    const tempDependencyDirs = [
+      getJavaTempDependencyDir(),
+      getCsharpTempDependencyDir()
+    ];
+    for (const tempDependencyDir of tempDependencyDirs) {
+      if (fs6.existsSync(tempDependencyDir)) {
+        try {
+          fs6.rmSync(tempDependencyDir, { recursive: true });
+        } catch (error4) {
+          logger.info(
+            `Failed to remove temporary dependencies directory: ${getErrorMessage(error4)}`
+          );
+        }
       }
     }
   } catch (error4) {
diff --git a/lib/analyze-action.js b/lib/analyze-action.js
index fd43a2f778..e5e897ca38 100644
--- a/lib/analyze-action.js
+++ b/lib/analyze-action.js
@@ -88658,6 +88658,11 @@ var featureConfig = {
     legacyApi: true,
     minimumVersion: "2.15.0"
   },
+  ["csharp_cache_bmn" /* CsharpCacheBuildModeNone */]: {
+    defaultValue: false,
+    envVar: "CODEQL_ACTION_CSHARP_CACHE_BMN",
+    minimumVersion: void 0
+  },
   ["csharp_new_cache_key" /* CsharpNewCacheKey */]: {
     defaultValue: false,
     envVar: "CODEQL_ACTION_CSHARP_NEW_CACHE_KEY",
@@ -91059,7 +91064,7 @@ var CODEQL_DEPENDENCY_CACHE_VERSION = 1;
 function getJavaTempDependencyDir() {
   return (0, import_path.join)(getTemporaryDirectory(), "codeql_java", "repository");
 }
-function getJavaDependencyDirs() {
+async function getJavaDependencyDirs() {
   return [
     // Maven
     (0, import_path.join)(os3.homedir(), ".m2", "repository"),
@@ -91069,6 +91074,19 @@ function getJavaDependencyDirs() {
     getJavaTempDependencyDir()
   ];
 }
+function getCsharpTempDependencyDir() {
+  return (0, import_path.join)(getTemporaryDirectory(), "codeql_csharp", "repository");
+}
+async function getCsharpDependencyDirs(codeql, features) {
+  const dirs = [
+    // Nuget
+    (0, import_path.join)(os3.homedir(), ".nuget", "packages")
+  ];
+  if (await features.getValue("csharp_cache_bmn" /* CsharpCacheBuildModeNone */, codeql)) {
+    dirs.push(getCsharpTempDependencyDir());
+  }
+  return dirs;
+}
 async function makePatternCheck(patterns) {
   const globber = await makeGlobber(patterns);
   if ((await globber.glob()).length === 0) {
@@ -91113,11 +91131,11 @@ var defaultCacheConfigs = {
     ])
   },
   csharp: {
-    getDependencyPaths: () => [(0, import_path.join)(os3.homedir(), ".nuget", "packages")],
+    getDependencyPaths: getCsharpDependencyDirs,
     getHashPatterns: getCsharpHashPatterns
   },
   go: {
-    getDependencyPaths: () => [(0, import_path.join)(os3.homedir(), "go", "pkg", "mod")],
+    getDependencyPaths: async () => [(0, import_path.join)(os3.homedir(), "go", "pkg", "mod")],
     getHashPatterns: async () => internal.makePatternCheck(["**/go.sum"])
   }
 };
@@ -91156,7 +91174,7 @@ async function uploadDependencyCaches(codeql, features, config, logger) {
       continue;
     }
     const size = await getTotalCacheSize(
-      cacheConfig.getDependencyPaths(),
+      await cacheConfig.getDependencyPaths(codeql, features),
       logger,
       true
     );
@@ -91173,7 +91191,10 @@ async function uploadDependencyCaches(codeql, features, config, logger) {
     );
     try {
       const start = performance.now();
-      await actionsCache3.saveCache(cacheConfig.getDependencyPaths(), key);
+      await actionsCache3.saveCache(
+        await cacheConfig.getDependencyPaths(codeql, features),
+        key
+      );
       const upload_duration_ms = Math.round(performance.now() - start);
       status.push({
         language,
@@ -91216,6 +91237,7 @@ async function getFeaturePrefix(codeql, features, language) {
     }
   } else if (language === "csharp" /* csharp */) {
     await addFeatureIfEnabled("csharp_new_cache_key" /* CsharpNewCacheKey */);
+    await addFeatureIfEnabled("csharp_cache_bmn" /* CsharpCacheBuildModeNone */);
   }
   if (enabledFeatures.length > 0) {
     return `${createCacheKeyHash(enabledFeatures)}-`;
@@ -91305,7 +91327,7 @@ async function setupPythonExtractor(logger) {
   );
   return;
 }
-async function runExtraction(codeql, config, logger) {
+async function runExtraction(codeql, features, config, logger) {
   for (const language of config.languages) {
     if (dbIsFinalized(config, language, logger)) {
       logger.debug(
@@ -91325,6 +91347,9 @@ async function runExtraction(codeql, config, logger) {
         if (language === "java" /* java */ && config.buildMode === "none" /* None */) {
           process.env["CODEQL_EXTRACTOR_JAVA_OPTION_BUILDLESS_DEPENDENCY_DIR"] = getJavaTempDependencyDir();
         }
+        if (language === "csharp" /* csharp */ && config.buildMode === "none" /* None */ && await features.getValue("csharp_cache_bmn" /* CsharpCacheBuildModeNone */)) {
+          process.env["CODEQL_EXTRACTOR_CSHARP_OPTION_BUILDLESS_DEPENDENCY_DIR"] = getCsharpTempDependencyDir();
+        }
         await codeql.extractUsingBuildMode(config, language);
       } else {
         await codeql.extractScannedLanguage(config, language);
@@ -91350,9 +91375,9 @@ function dbIsFinalized(config, language, logger) {
     return false;
   }
 }
-async function finalizeDatabaseCreation(codeql, config, threadsFlag, memoryFlag, logger) {
+async function finalizeDatabaseCreation(codeql, features, config, threadsFlag, memoryFlag, logger) {
   const extractionStart = import_perf_hooks2.performance.now();
-  await runExtraction(codeql, config, logger);
+  await runExtraction(codeql, features, config, logger);
   const extractionTime = import_perf_hooks2.performance.now() - extractionStart;
   const trapImportStart = import_perf_hooks2.performance.now();
   for (const language of config.languages) {
@@ -91607,7 +91632,7 @@ async function runQueries(sarifFolder, memoryFlag, threadsFlag, diffRangePackDir
     return perQueryAlertCounts;
   }
 }
-async function runFinalize(outputDir, threadsFlag, memoryFlag, codeql, config, logger) {
+async function runFinalize(features, outputDir, threadsFlag, memoryFlag, codeql, config, logger) {
   try {
     await fs12.promises.rm(outputDir, { force: true, recursive: true });
   } catch (error4) {
@@ -91618,6 +91643,7 @@ async function runFinalize(outputDir, threadsFlag, memoryFlag, codeql, config, l
   await fs12.promises.mkdir(outputDir, { recursive: true });
   const timings = await finalizeDatabaseCreation(
     codeql,
+    features,
     config,
     threadsFlag,
     memoryFlag,
@@ -93952,6 +93978,7 @@ async function run() {
     await warnIfGoInstalledAfterInit(config, logger);
     await runAutobuildIfLegacyGoWorkflow(config, logger);
     dbCreationTimings = await runFinalize(
+      features,
       outputDir,
       threads,
       memory,
diff --git a/lib/autobuild-action.js b/lib/autobuild-action.js
index d09fe07d82..48485a850d 100644
--- a/lib/autobuild-action.js
+++ b/lib/autobuild-action.js
@@ -83977,6 +83977,11 @@ var featureConfig = {
     legacyApi: true,
     minimumVersion: "2.15.0"
   },
+  ["csharp_cache_bmn" /* CsharpCacheBuildModeNone */]: {
+    defaultValue: false,
+    envVar: "CODEQL_ACTION_CSHARP_CACHE_BMN",
+    minimumVersion: void 0
+  },
   ["csharp_new_cache_key" /* CsharpNewCacheKey */]: {
     defaultValue: false,
     envVar: "CODEQL_ACTION_CSHARP_NEW_CACHE_KEY",
diff --git a/lib/init-action-post.js b/lib/init-action-post.js
index 1d3c4d5d93..b15b16f377 100644
--- a/lib/init-action-post.js
+++ b/lib/init-action-post.js
@@ -123309,6 +123309,11 @@ var featureConfig = {
     legacyApi: true,
     minimumVersion: "2.15.0"
   },
+  ["csharp_cache_bmn" /* CsharpCacheBuildModeNone */]: {
+    defaultValue: false,
+    envVar: "CODEQL_ACTION_CSHARP_CACHE_BMN",
+    minimumVersion: void 0
+  },
   ["csharp_new_cache_key" /* CsharpNewCacheKey */]: {
     defaultValue: false,
     envVar: "CODEQL_ACTION_CSHARP_NEW_CACHE_KEY",
diff --git a/lib/init-action.js b/lib/init-action.js
index 98c23c88fd..8d63c95de0 100644
--- a/lib/init-action.js
+++ b/lib/init-action.js
@@ -86072,6 +86072,11 @@ var featureConfig = {
     legacyApi: true,
     minimumVersion: "2.15.0"
   },
+  ["csharp_cache_bmn" /* CsharpCacheBuildModeNone */]: {
+    defaultValue: false,
+    envVar: "CODEQL_ACTION_CSHARP_CACHE_BMN",
+    minimumVersion: void 0
+  },
   ["csharp_new_cache_key" /* CsharpNewCacheKey */]: {
     defaultValue: false,
     envVar: "CODEQL_ACTION_CSHARP_NEW_CACHE_KEY",
@@ -87246,7 +87251,7 @@ var CODEQL_DEPENDENCY_CACHE_VERSION = 1;
 function getJavaTempDependencyDir() {
   return (0, import_path.join)(getTemporaryDirectory(), "codeql_java", "repository");
 }
-function getJavaDependencyDirs() {
+async function getJavaDependencyDirs() {
   return [
     // Maven
     (0, import_path.join)(os2.homedir(), ".m2", "repository"),
@@ -87256,6 +87261,19 @@ function getJavaDependencyDirs() {
     getJavaTempDependencyDir()
   ];
 }
+function getCsharpTempDependencyDir() {
+  return (0, import_path.join)(getTemporaryDirectory(), "codeql_csharp", "repository");
+}
+async function getCsharpDependencyDirs(codeql, features) {
+  const dirs = [
+    // Nuget
+    (0, import_path.join)(os2.homedir(), ".nuget", "packages")
+  ];
+  if (await features.getValue("csharp_cache_bmn" /* CsharpCacheBuildModeNone */, codeql)) {
+    dirs.push(getCsharpTempDependencyDir());
+  }
+  return dirs;
+}
 async function makePatternCheck(patterns) {
   const globber = await makeGlobber(patterns);
   if ((await globber.glob()).length === 0) {
@@ -87300,11 +87318,11 @@ var defaultCacheConfigs = {
     ])
   },
   csharp: {
-    getDependencyPaths: () => [(0, import_path.join)(os2.homedir(), ".nuget", "packages")],
+    getDependencyPaths: getCsharpDependencyDirs,
     getHashPatterns: getCsharpHashPatterns
   },
   go: {
-    getDependencyPaths: () => [(0, import_path.join)(os2.homedir(), "go", "pkg", "mod")],
+    getDependencyPaths: async () => [(0, import_path.join)(os2.homedir(), "go", "pkg", "mod")],
     getHashPatterns: async () => internal.makePatternCheck(["**/go.sum"])
   }
 };
@@ -87353,7 +87371,7 @@ async function downloadDependencyCaches(codeql, features, languages, logger) {
     );
     const start = performance.now();
     const hitKey = await actionsCache3.restoreCache(
-      cacheConfig.getDependencyPaths(),
+      await cacheConfig.getDependencyPaths(codeql, features),
       primaryKey,
       restoreKeys
     );
@@ -87390,6 +87408,7 @@ async function getFeaturePrefix(codeql, features, language) {
     }
   } else if (language === "csharp" /* csharp */) {
     await addFeatureIfEnabled("csharp_new_cache_key" /* CsharpNewCacheKey */);
+    await addFeatureIfEnabled("csharp_cache_bmn" /* CsharpCacheBuildModeNone */);
   }
   if (enabledFeatures.length > 0) {
     return `${createCacheKeyHash(enabledFeatures)}-`;
diff --git a/lib/resolve-environment-action.js b/lib/resolve-environment-action.js
index 7918ab61f7..766a59c171 100644
--- a/lib/resolve-environment-action.js
+++ b/lib/resolve-environment-action.js
@@ -83968,6 +83968,11 @@ var featureConfig = {
     legacyApi: true,
     minimumVersion: "2.15.0"
   },
+  ["csharp_cache_bmn" /* CsharpCacheBuildModeNone */]: {
+    defaultValue: false,
+    envVar: "CODEQL_ACTION_CSHARP_CACHE_BMN",
+    minimumVersion: void 0
+  },
   ["csharp_new_cache_key" /* CsharpNewCacheKey */]: {
     defaultValue: false,
     envVar: "CODEQL_ACTION_CSHARP_NEW_CACHE_KEY",
diff --git a/lib/setup-codeql-action.js b/lib/setup-codeql-action.js
index c9e95730bf..f00d601e7d 100644
--- a/lib/setup-codeql-action.js
+++ b/lib/setup-codeql-action.js
@@ -83880,6 +83880,11 @@ var featureConfig = {
     legacyApi: true,
     minimumVersion: "2.15.0"
   },
+  ["csharp_cache_bmn" /* CsharpCacheBuildModeNone */]: {
+    defaultValue: false,
+    envVar: "CODEQL_ACTION_CSHARP_CACHE_BMN",
+    minimumVersion: void 0
+  },
   ["csharp_new_cache_key" /* CsharpNewCacheKey */]: {
     defaultValue: false,
     envVar: "CODEQL_ACTION_CSHARP_NEW_CACHE_KEY",
diff --git a/lib/start-proxy-action-post.js b/lib/start-proxy-action-post.js
index 2386e7c27b..85e0aaeb08 100644
--- a/lib/start-proxy-action-post.js
+++ b/lib/start-proxy-action-post.js
@@ -119334,6 +119334,11 @@ var featureConfig = {
     legacyApi: true,
     minimumVersion: "2.15.0"
   },
+  ["csharp_cache_bmn" /* CsharpCacheBuildModeNone */]: {
+    defaultValue: false,
+    envVar: "CODEQL_ACTION_CSHARP_CACHE_BMN",
+    minimumVersion: void 0
+  },
   ["csharp_new_cache_key" /* CsharpNewCacheKey */]: {
     defaultValue: false,
     envVar: "CODEQL_ACTION_CSHARP_NEW_CACHE_KEY",
diff --git a/lib/start-proxy-action.js b/lib/start-proxy-action.js
index 281341e5aa..5613603cb9 100644
--- a/lib/start-proxy-action.js
+++ b/lib/start-proxy-action.js
@@ -99996,6 +99996,11 @@ var featureConfig = {
     legacyApi: true,
     minimumVersion: "2.15.0"
   },
+  ["csharp_cache_bmn" /* CsharpCacheBuildModeNone */]: {
+    defaultValue: false,
+    envVar: "CODEQL_ACTION_CSHARP_CACHE_BMN",
+    minimumVersion: void 0
+  },
   ["csharp_new_cache_key" /* CsharpNewCacheKey */]: {
     defaultValue: false,
     envVar: "CODEQL_ACTION_CSHARP_NEW_CACHE_KEY",
diff --git a/lib/upload-lib.js b/lib/upload-lib.js
index 2e980ba467..a0d12250c7 100644
--- a/lib/upload-lib.js
+++ b/lib/upload-lib.js
@@ -87034,6 +87034,11 @@ var featureConfig = {
     legacyApi: true,
     minimumVersion: "2.15.0"
   },
+  ["csharp_cache_bmn" /* CsharpCacheBuildModeNone */]: {
+    defaultValue: false,
+    envVar: "CODEQL_ACTION_CSHARP_CACHE_BMN",
+    minimumVersion: void 0
+  },
   ["csharp_new_cache_key" /* CsharpNewCacheKey */]: {
     defaultValue: false,
     envVar: "CODEQL_ACTION_CSHARP_NEW_CACHE_KEY",
diff --git a/lib/upload-sarif-action-post.js b/lib/upload-sarif-action-post.js
index 1d2a3a44b3..1d63547086 100644
--- a/lib/upload-sarif-action-post.js
+++ b/lib/upload-sarif-action-post.js
@@ -119500,6 +119500,11 @@ var featureConfig = {
     legacyApi: true,
     minimumVersion: "2.15.0"
   },
+  ["csharp_cache_bmn" /* CsharpCacheBuildModeNone */]: {
+    defaultValue: false,
+    envVar: "CODEQL_ACTION_CSHARP_CACHE_BMN",
+    minimumVersion: void 0
+  },
   ["csharp_new_cache_key" /* CsharpNewCacheKey */]: {
     defaultValue: false,
     envVar: "CODEQL_ACTION_CSHARP_NEW_CACHE_KEY",
diff --git a/lib/upload-sarif-action.js b/lib/upload-sarif-action.js
index 6fd196c32e..1266953f0c 100644
--- a/lib/upload-sarif-action.js
+++ b/lib/upload-sarif-action.js
@@ -86830,6 +86830,11 @@ var featureConfig = {
     legacyApi: true,
     minimumVersion: "2.15.0"
   },
+  ["csharp_cache_bmn" /* CsharpCacheBuildModeNone */]: {
+    defaultValue: false,
+    envVar: "CODEQL_ACTION_CSHARP_CACHE_BMN",
+    minimumVersion: void 0
+  },
   ["csharp_new_cache_key" /* CsharpNewCacheKey */]: {
     defaultValue: false,
     envVar: "CODEQL_ACTION_CSHARP_NEW_CACHE_KEY",
diff --git a/src/analyze-action-env.test.ts b/src/analyze-action-env.test.ts
index e4960a5803..aecbae4b02 100644
--- a/src/analyze-action-env.test.ts
+++ b/src/analyze-action-env.test.ts
@@ -74,11 +74,20 @@ test("analyze action with RAM & threads from environment variables", async (t) =
     // wait for the action promise to complete before starting verification.
     await analyzeAction.runPromise;
 
-    t.assert(runFinalizeStub.calledOnce);
-    t.deepEqual(runFinalizeStub.firstCall.args[1], "--threads=-1");
-    t.deepEqual(runFinalizeStub.firstCall.args[2], "--ram=4992");
-    t.assert(runQueriesStub.calledOnce);
-    t.deepEqual(runQueriesStub.firstCall.args[2], "--threads=-1");
-    t.deepEqual(runQueriesStub.firstCall.args[1], "--ram=4992");
+    t.assert(
+      runFinalizeStub.calledOnceWith(
+        sinon.match.any,
+        sinon.match.any,
+        "--threads=-1",
+        "--ram=4992",
+      ),
+    );
+    t.assert(
+      runQueriesStub.calledOnceWith(
+        sinon.match.any,
+        "--ram=4992",
+        "--threads=-1",
+      ),
+    );
   });
 });
diff --git a/src/analyze-action-input.test.ts b/src/analyze-action-input.test.ts
index 48fa216ebf..74c03923da 100644
--- a/src/analyze-action-input.test.ts
+++ b/src/analyze-action-input.test.ts
@@ -72,11 +72,20 @@ test("analyze action with RAM & threads from action inputs", async (t) => {
     // wait for the action promise to complete before starting verification.
     await analyzeAction.runPromise;
 
-    t.assert(runFinalizeStub.calledOnce);
-    t.deepEqual(runFinalizeStub.firstCall.args[1], "--threads=-1");
-    t.deepEqual(runFinalizeStub.firstCall.args[2], "--ram=3012");
-    t.assert(runQueriesStub.calledOnce);
-    t.deepEqual(runQueriesStub.firstCall.args[2], "--threads=-1");
-    t.deepEqual(runQueriesStub.firstCall.args[1], "--ram=3012");
+    t.assert(
+      runFinalizeStub.calledOnceWith(
+        sinon.match.any,
+        sinon.match.any,
+        "--threads=-1",
+        "--ram=3012",
+      ),
+    );
+    t.assert(
+      runQueriesStub.calledOnceWith(
+        sinon.match.any,
+        "--ram=3012",
+        "--threads=-1",
+      ),
+    );
   });
 });
diff --git a/src/analyze-action-post.ts b/src/analyze-action-post.ts
index 1f91b4f0fd..ce8ddd31bb 100644
--- a/src/analyze-action-post.ts
+++ b/src/analyze-action-post.ts
@@ -12,7 +12,10 @@ import { getGitHubVersion } from "./api-client";
 import { getCodeQL } from "./codeql";
 import { getConfig } from "./config-utils";
 import * as debugArtifacts from "./debug-artifacts";
-import { getJavaTempDependencyDir } from "./dependency-caching";
+import {
+  getCsharpTempDependencyDir,
+  getJavaTempDependencyDir,
+} from "./dependency-caching";
 import { EnvVar } from "./environment";
 import { getActionsLogger } from "./logging";
 import { checkGitHubVersionInRange, getErrorMessage } from "./util";
@@ -42,17 +45,22 @@ async function runWrapper() {
       }
     }
 
-    // If we analysed Java in build-mode: none, we may have downloaded dependencies
+    // If we analysed Java or C# in build-mode: none, we may have downloaded dependencies
     // to the temp directory. Clean these up so they don't persist unnecessarily
     // long on self-hosted runners.
-    const javaTempDependencyDir = getJavaTempDependencyDir();
-    if (fs.existsSync(javaTempDependencyDir)) {
-      try {
-        fs.rmSync(javaTempDependencyDir, { recursive: true });
-      } catch (error) {
-        logger.info(
-          `Failed to remove temporary Java dependencies directory: ${getErrorMessage(error)}`,
-        );
+    const tempDependencyDirs = [
+      getJavaTempDependencyDir(),
+      getCsharpTempDependencyDir(),
+    ];
+    for (const tempDependencyDir of tempDependencyDirs) {
+      if (fs.existsSync(tempDependencyDir)) {
+        try {
+          fs.rmSync(tempDependencyDir, { recursive: true });
+        } catch (error) {
+          logger.info(
+            `Failed to remove temporary dependencies directory: ${getErrorMessage(error)}`,
+          );
+        }
       }
     }
   } catch (error) {
diff --git a/src/analyze-action.ts b/src/analyze-action.ts
index 3ab1dd1321..0349c13c30 100644
--- a/src/analyze-action.ts
+++ b/src/analyze-action.ts
@@ -315,6 +315,7 @@ async function run() {
     await runAutobuildIfLegacyGoWorkflow(config, logger);
 
     dbCreationTimings = await runFinalize(
+      features,
       outputDir,
       threads,
       memory,
diff --git a/src/analyze.ts b/src/analyze.ts
index cd82ad61b1..dc631ba98f 100644
--- a/src/analyze.ts
+++ b/src/analyze.ts
@@ -10,7 +10,10 @@ import * as analyses from "./analyses";
 import { setupCppAutobuild } from "./autobuild";
 import { type CodeQL } from "./codeql";
 import * as configUtils from "./config-utils";
-import { getJavaTempDependencyDir } from "./dependency-caching";
+import {
+  getCsharpTempDependencyDir,
+  getJavaTempDependencyDir,
+} from "./dependency-caching";
 import { addDiagnostic, makeDiagnostic } from "./diagnostics";
 import {
   DiffThunkRange,
@@ -98,6 +101,7 @@ async function setupPythonExtractor(logger: Logger) {
 
 export async function runExtraction(
   codeql: CodeQL,
+  features: FeatureEnablement,
   config: configUtils.Config,
   logger: Logger,
 ) {
@@ -122,7 +126,7 @@ export async function runExtraction(
           await setupCppAutobuild(codeql, logger);
         }
 
-        // The Java `build-mode: none` extractor places dependencies (.jar files) in the
+        // The Java and C# `build-mode: none` extractors place dependencies in the
         // database scratch directory by default. For dependency caching purposes, we want
         // a stable path that caches can be restored into and that we can cache at the
         // end of the workflow (i.e. that does not get removed when the scratch directory is).
@@ -133,6 +137,15 @@ export async function runExtraction(
           process.env["CODEQL_EXTRACTOR_JAVA_OPTION_BUILDLESS_DEPENDENCY_DIR"] =
             getJavaTempDependencyDir();
         }
+        if (
+          language === KnownLanguage.csharp &&
+          config.buildMode === BuildMode.None &&
+          (await features.getValue(Feature.CsharpCacheBuildModeNone))
+        ) {
+          process.env[
+            "CODEQL_EXTRACTOR_CSHARP_OPTION_BUILDLESS_DEPENDENCY_DIR"
+          ] = getCsharpTempDependencyDir();
+        }
 
         await codeql.extractUsingBuildMode(config, language);
       } else {
@@ -177,13 +190,14 @@ export function dbIsFinalized(
 
 async function finalizeDatabaseCreation(
   codeql: CodeQL,
+  features: FeatureEnablement,
   config: configUtils.Config,
   threadsFlag: string,
   memoryFlag: string,
   logger: Logger,
 ): Promise<DatabaseCreationTimings> {
   const extractionStart = performance.now();
-  await runExtraction(codeql, config, logger);
+  await runExtraction(codeql, features, config, logger);
   const extractionTime = performance.now() - extractionStart;
 
   const trapImportStart = performance.now();
@@ -597,6 +611,7 @@ export async function runQueries(
 }
 
 export async function runFinalize(
+  features: FeatureEnablement,
   outputDir: string,
   threadsFlag: string,
   memoryFlag: string,
@@ -615,6 +630,7 @@ export async function runFinalize(
 
   const timings = await finalizeDatabaseCreation(
     codeql,
+    features,
     config,
     threadsFlag,
     memoryFlag,
diff --git a/src/dependency-caching.test.ts b/src/dependency-caching.test.ts
index eefb8504cd..bf2f7ba74d 100644
--- a/src/dependency-caching.test.ts
+++ b/src/dependency-caching.test.ts
@@ -20,6 +20,8 @@ import {
   downloadDependencyCaches,
   CacheHitKind,
   cacheKey,
+  getCsharpDependencyDirs,
+  getCsharpTempDependencyDir,
 } from "./dependency-caching";
 import { Feature } from "./feature-flags";
 import { KnownLanguage } from "./languages";
@@ -38,6 +40,28 @@ function makeAbsolutePatterns(tmpDir: string, patterns: string[]): string[] {
   return patterns.map((pattern) => path.join(tmpDir, pattern));
 }
 
+test("getCsharpDependencyDirs - does not include BMN dir if FF is enabled", async (t) => {
+  await withTmpDir(async (tmpDir) => {
+    process.env["RUNNER_TEMP"] = tmpDir;
+    const codeql = createStubCodeQL({});
+    const features = createFeatures([]);
+
+    const results = await getCsharpDependencyDirs(codeql, features);
+    t.false(results.includes(getCsharpTempDependencyDir()));
+  });
+});
+
+test("getCsharpDependencyDirs - includes BMN dir if FF is enabled", async (t) => {
+  await withTmpDir(async (tmpDir) => {
+    process.env["RUNNER_TEMP"] = tmpDir;
+    const codeql = createStubCodeQL({});
+    const features = createFeatures([Feature.CsharpCacheBuildModeNone]);
+
+    const results = await getCsharpDependencyDirs(codeql, features);
+    t.assert(results.includes(getCsharpTempDependencyDir()));
+  });
+});
+
 test("makePatternCheck - returns undefined if no patterns match", async (t) => {
   await withTmpDir(async (tmpDir) => {
     fs.writeFileSync(path.join(tmpDir, "test.java"), "");
@@ -126,7 +150,7 @@ test("checkHashPatterns - logs when no patterns match", async (t) => {
   const features = createFeatures([]);
   const messages: LoggedMessage[] = [];
   const config: CacheConfig = {
-    getDependencyPaths: () => [],
+    getDependencyPaths: async () => [],
     getHashPatterns: async () => undefined,
   };
 
@@ -155,7 +179,7 @@ test("checkHashPatterns - returns patterns when patterns match", async (t) => {
     fs.writeFileSync(path.join(tmpDir, "test.java"), "");
 
     const config: CacheConfig = {
-      getDependencyPaths: () => [],
+      getDependencyPaths: async () => [],
       getHashPatterns: async () => makePatternCheck(patterns),
     };
 
@@ -387,3 +411,28 @@ test("getFeaturePrefix - non-C# - returns '' if CsharpNewCacheKey is enabled", a
     t.deepEqual(result, "", `Expected no feature prefix for ${knownLanguage}`);
   }
 });
+
+test("getFeaturePrefix - C# - returns prefix if CsharpCacheBuildModeNone is enabled", async (t) => {
+  const codeql = createStubCodeQL({});
+  const features = createFeatures([Feature.CsharpCacheBuildModeNone]);
+
+  const result = await getFeaturePrefix(codeql, features, KnownLanguage.csharp);
+  t.notDeepEqual(result, "");
+  t.assert(result.endsWith("-"));
+  // Check the length of the prefix, which should correspond to `cacheKeyHashLength` + 1 for the trailing `-`.
+  t.is(result.length, cacheKeyHashLength + 1);
+});
+
+test("getFeaturePrefix - non-C# - returns '' if CsharpCacheBuildModeNone is enabled", async (t) => {
+  const codeql = createStubCodeQL({});
+  const features = createFeatures([Feature.CsharpCacheBuildModeNone]);
+
+  for (const knownLanguage of Object.values(KnownLanguage)) {
+    // Skip C# since we expect a result for it, which is tested in the previous test.
+    if (knownLanguage === KnownLanguage.csharp) {
+      continue;
+    }
+    const result = await getFeaturePrefix(codeql, features, knownLanguage);
+    t.deepEqual(result, "", `Expected no feature prefix for ${knownLanguage}`);
+  }
+});
diff --git a/src/dependency-caching.ts b/src/dependency-caching.ts
index 220f1d5bab..bd39bad751 100644
--- a/src/dependency-caching.ts
+++ b/src/dependency-caching.ts
@@ -20,7 +20,10 @@ import { getErrorMessage, getRequiredEnvParam } from "./util";
  */
 export interface CacheConfig {
   /** Gets the paths of directories on the runner that should be included in the cache. */
-  getDependencyPaths: () => string[];
+  getDependencyPaths: (
+    codeql: CodeQL,
+    features: FeatureEnablement,
+  ) => Promise<string[]>;
   /**
    * Gets an array of glob patterns for the paths of files whose contents affect which dependencies are used
    * by a project. This function also checks whether there are any matching files and returns
@@ -55,7 +58,7 @@ export function getJavaTempDependencyDir(): string {
  * @returns The paths of directories on the runner that should be included in a dependency cache
  * for a Java analysis.
  */
-export function getJavaDependencyDirs(): string[] {
+export async function getJavaDependencyDirs(): Promise<string[]> {
   return [
     // Maven
     join(os.homedir(), ".m2", "repository"),
@@ -66,6 +69,38 @@ export function getJavaDependencyDirs(): string[] {
   ];
 }
 
+/**
+ * Returns a path to a directory intended to be used to store dependencies
+ * for the C# `build-mode: none` extractor.
+ * @returns The path to the directory that should be used by the `build-mode: none` extractor.
+ */
+export function getCsharpTempDependencyDir(): string {
+  return join(getTemporaryDirectory(), "codeql_csharp", "repository");
+}
+
+/**
+ * Returns an array of paths of directories on the runner that should be included in a dependency cache
+ * for a C# analysis.
+ *
+ * @returns The paths of directories on the runner that should be included in a dependency cache
+ * for a C# analysis.
+ */
+export async function getCsharpDependencyDirs(
+  codeql: CodeQL,
+  features: FeatureEnablement,
+): Promise<string[]> {
+  const dirs = [
+    // Nuget
+    join(os.homedir(), ".nuget", "packages"),
+  ];
+
+  if (await features.getValue(Feature.CsharpCacheBuildModeNone, codeql)) {
+    dirs.push(getCsharpTempDependencyDir());
+  }
+
+  return dirs;
+}
+
 /**
  * Checks that there are files which match `patterns`. If there are matching files for any of the patterns,
  * this function returns all `patterns`. Otherwise, `undefined` is returned.
@@ -158,11 +193,11 @@ const defaultCacheConfigs: { [language: string]: CacheConfig } = {
       ]),
   },
   csharp: {
-    getDependencyPaths: () => [join(os.homedir(), ".nuget", "packages")],
+    getDependencyPaths: getCsharpDependencyDirs,
     getHashPatterns: getCsharpHashPatterns,
   },
   go: {
-    getDependencyPaths: () => [join(os.homedir(), "go", "pkg", "mod")],
+    getDependencyPaths: async () => [join(os.homedir(), "go", "pkg", "mod")],
     getHashPatterns: async () => internal.makePatternCheck(["**/go.sum"]),
   },
 };
@@ -280,7 +315,7 @@ export async function downloadDependencyCaches(
 
     const start = performance.now();
     const hitKey = await actionsCache.restoreCache(
-      cacheConfig.getDependencyPaths(),
+      await cacheConfig.getDependencyPaths(codeql, features),
       primaryKey,
       restoreKeys,
     );
@@ -376,7 +411,7 @@ export async function uploadDependencyCaches(
     //   with the dependency caches. For this, we could use the Cache API to check whether other workflows
     //   are using the quota and how full it is.
     const size = await getTotalCacheSize(
-      cacheConfig.getDependencyPaths(),
+      await cacheConfig.getDependencyPaths(codeql, features),
       logger,
       true,
     );
@@ -398,7 +433,10 @@ export async function uploadDependencyCaches(
 
     try {
       const start = performance.now();
-      await actionsCache.saveCache(cacheConfig.getDependencyPaths(), key);
+      await actionsCache.saveCache(
+        await cacheConfig.getDependencyPaths(codeql, features),
+        key,
+      );
       const upload_duration_ms = Math.round(performance.now() - start);
 
       status.push({
@@ -486,6 +524,7 @@ export async function getFeaturePrefix(
     }
   } else if (language === KnownLanguage.csharp) {
     await addFeatureIfEnabled(Feature.CsharpNewCacheKey);
+    await addFeatureIfEnabled(Feature.CsharpCacheBuildModeNone);
   }
 
   // If any features that affect the cache are enabled, return a feature prefix by
diff --git a/src/feature-flags.ts b/src/feature-flags.ts
index 1334969795..27a3c0f4f7 100644
--- a/src/feature-flags.ts
+++ b/src/feature-flags.ts
@@ -47,6 +47,7 @@ export enum Feature {
   AnalyzeUseNewUpload = "analyze_use_new_upload",
   CleanupTrapCaches = "cleanup_trap_caches",
   CppDependencyInstallation = "cpp_dependency_installation_enabled",
+  CsharpCacheBuildModeNone = "csharp_cache_bmn",
   CsharpNewCacheKey = "csharp_new_cache_key",
   DiffInformedQueries = "diff_informed_queries",
   DisableCsharpBuildless = "disable_csharp_buildless",
@@ -133,6 +134,11 @@ export const featureConfig: Record<
     legacyApi: true,
     minimumVersion: "2.15.0",
   },
+  [Feature.CsharpCacheBuildModeNone]: {
+    defaultValue: false,
+    envVar: "CODEQL_ACTION_CSHARP_CACHE_BMN",
+    minimumVersion: undefined,
+  },
   [Feature.CsharpNewCacheKey]: {
     defaultValue: false,
     envVar: "CODEQL_ACTION_CSHARP_NEW_CACHE_KEY",