diff --git a/src/colony_sdk/client.py b/src/colony_sdk/client.py
index e7ed3e5..18151ed 100644
--- a/src/colony_sdk/client.py
+++ b/src/colony_sdk/client.py
@@ -375,6 +375,15 @@ def get_colonies(self, limit: int = 50) -> dict:
         params = urlencode({"limit": str(limit)})
         return self._raw_request("GET", f"/colonies?{params}")
 
+    def join_colony(self, colony: str) -> dict:
+        """Join a colony.
+
+        Args:
+            colony: Colony name (e.g. ``"general"``, ``"findings"``) or UUID.
+        """
+        colony_id = COLONIES.get(colony, colony)
+        return self._raw_request("POST", f"/colonies/{colony_id}/join")
+
     # ── Unread messages ──────────────────────────────────────────────
 
     def get_unread_count(self) -> dict:
diff --git a/tests/test_api_methods.py b/tests/test_api_methods.py
index 6ef9b2a..d1161b8 100644
--- a/tests/test_api_methods.py
+++ b/tests/test_api_methods.py
@@ -663,6 +663,28 @@ def test_get_colonies(self, mock_urlopen: MagicMock) -> None:
         assert req.get_method() == "GET"
         assert "limit=10" in req.full_url
 
+    @patch("colony_sdk.client.urlopen")
+    def test_join_colony_by_name(self, mock_urlopen: MagicMock) -> None:
+        mock_urlopen.return_value = _mock_response({"joined": True})
+        client = _authed_client()
+
+        client.join_colony("general")
+
+        req = _last_request(mock_urlopen)
+        assert req.get_method() == "POST"
+        assert req.full_url == f"{BASE}/colonies/{COLONIES['general']}/join"
+
+    @patch("colony_sdk.client.urlopen")
+    def test_join_colony_by_uuid(self, mock_urlopen: MagicMock) -> None:
+        mock_urlopen.return_value = _mock_response({"joined": True})
+        client = _authed_client()
+        custom_uuid = "aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee"
+
+        client.join_colony(custom_uuid)
+
+        req = _last_request(mock_urlopen)
+        assert req.full_url == f"{BASE}/colonies/{custom_uuid}/join"
+
 
 # ---------------------------------------------------------------------------
 # Registration