diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3f2237dc7..b0e230bf7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,8 @@
 
 ## [Unreleased]
 
+- Speed up importing pystac ([#1584](https://github.com/stac-utils/pystac/pull/1584))
+
 ## [v1.14.1] - 2025-09-18
 
 ### Fixed
diff --git a/pystac/__init__.py b/pystac/__init__.py
index 1fbbb8343..20be20f10 100644
--- a/pystac/__init__.py
+++ b/pystac/__init__.py
@@ -44,7 +44,6 @@
     "set_stac_version",
 ]
 
-import os
 import warnings
 from typing import Any
 
@@ -199,6 +198,8 @@ def write_file(
     """
     if stac_io is None:
         stac_io = StacIO.default()
+    import os
+
     dest_href = None if dest_href is None else str(os.fspath(dest_href))
     obj.save_object(
         include_self_link=include_self_link, dest_href=dest_href, stac_io=stac_io
diff --git a/pystac/asset.py b/pystac/asset.py
index 46d034bf7..32bbfadb8 100644
--- a/pystac/asset.py
+++ b/pystac/asset.py
@@ -1,13 +1,10 @@
 from __future__ import annotations
 
-import os
 import shutil
 from copy import copy, deepcopy
-from html import escape
 from typing import TYPE_CHECKING, Any, Protocol, TypeVar
 
 from pystac import MediaType, STACError, common_metadata, utils
-from pystac.html.jinja_env import get_jinja_env
 from pystac.utils import is_absolute_href, make_absolute_href, make_relative_href
 
 if TYPE_CHECKING:
@@ -182,6 +179,10 @@ def __repr__(self) -> str:
         return f"<Asset href={self.href}>"
 
     def _repr_html_(self) -> str:
+        from html import escape
+
+        from pystac.html.jinja_env import get_jinja_env
+
         jinja_env = get_jinja_env()
         if jinja_env:
             template = jinja_env.get_template("JSON.jinja2")
@@ -259,6 +260,8 @@ def delete(self) -> None:
 
         Does not modify the asset.
         """
+        import os
+
         href = _absolute_href(self.href, self.owner, "delete")
         os.remove(href)
 
diff --git a/pystac/catalog.py b/pystac/catalog.py
index ae47787c0..aae2612f3 100644
--- a/pystac/catalog.py
+++ b/pystac/catalog.py
@@ -1,10 +1,8 @@
 from __future__ import annotations
 
 import os
-import warnings
 from collections.abc import Callable, Iterable, Iterator
 from copy import deepcopy
-from itertools import chain
 from typing import (
     TYPE_CHECKING,
     Any,
@@ -521,6 +519,8 @@ def get_item(self, id: str, recursive: bool = False) -> Item | None:
         Return:
             Item or None: The item with the given ID, or None if not found.
         """
+        import warnings
+
         warnings.warn(
             "get_item is deprecated and will be removed in v2. "
             "Use next(self.get_items(id), None) instead",
@@ -549,6 +549,8 @@ def get_items(self, *ids: str, recursive: bool = False) -> Iterator[Item]:
                 (if recursive) all catalogs or collections connected to this catalog
                 through child links.
         """
+        from itertools import chain
+
         items: Iterator[Item]
         if not recursive:
             items = map(
@@ -615,6 +617,9 @@ def get_all_items(self) -> Iterator[Item]:
                 catalogs or collections connected to this catalog through
                 child links.
         """
+        import warnings
+        from itertools import chain
+
         warnings.warn(
             "get_all_items is deprecated and will be removed in v2",
             DeprecationWarning,
diff --git a/pystac/collection.py b/pystac/collection.py
index be8693d6c..536fd2830 100644
--- a/pystac/collection.py
+++ b/pystac/collection.py
@@ -1,6 +1,5 @@
 from __future__ import annotations
 
-import warnings
 from collections.abc import Iterable, Sequence
 from copy import deepcopy
 from datetime import datetime, timezone
@@ -12,8 +11,6 @@
     cast,
 )
 
-from dateutil import tz
-
 import pystac
 from pystac import CatalogType, STACObjectType
 from pystac.asset import Asset, Assets
@@ -257,6 +254,8 @@ def from_dict(d: dict[str, Any]) -> TemporalExtent:
         parsed_intervals: list[list[datetime | None]] = []
         for i in d["interval"]:
             if isinstance(i, str):
+                import warnings
+
                 # d["interval"] is a list of strings, so we correct the list and
                 # try again
                 # https://github.com/stac-utils/pystac/issues/1221
@@ -384,6 +383,8 @@ def from_items(
             Extent: An Extent that spatially and temporally covers all of the
             given items.
         """
+        from dateutil import tz
+
         bounds_values: list[list[float]] = [
             [float("inf")],
             [float("inf")],
@@ -635,6 +636,8 @@ def from_dict(
         migrate: bool = True,
         preserve_dict: bool = True,
     ) -> C:
+        import warnings
+
         from pystac.extensions.version import CollectionVersionExtension
 
         if migrate:
diff --git a/pystac/extensions/eo.py b/pystac/extensions/eo.py
index 4de7a0268..1f4b12249 100644
--- a/pystac/extensions/eo.py
+++ b/pystac/extensions/eo.py
@@ -2,7 +2,6 @@
 
 from __future__ import annotations
 
-import warnings
 from collections.abc import Iterable
 from typing import (
     Any,
@@ -386,6 +385,8 @@ def get_schema_uri(cls) -> str:
 
     @classmethod
     def get_schema_uris(cls) -> list[str]:
+        import warnings
+
         warnings.warn(
             "get_schema_uris is deprecated and will be removed in v2",
             DeprecationWarning,
diff --git a/pystac/extensions/file.py b/pystac/extensions/file.py
index 61349ef83..b772123bf 100644
--- a/pystac/extensions/file.py
+++ b/pystac/extensions/file.py
@@ -2,7 +2,6 @@
 
 from __future__ import annotations
 
-import warnings
 from collections.abc import Iterable
 from typing import Any, Generic, Literal, TypeVar, cast
 
@@ -370,6 +369,8 @@ def migrate(
                 found_fields[asset_key] = values
 
         if found_fields:
+            import warnings
+
             warnings.warn(
                 f"Assets {list(found_fields.keys())} contain fields: "
                 f"{list(set.union(*found_fields.values()))} which "
diff --git a/pystac/extensions/grid.py b/pystac/extensions/grid.py
index 112fe75cb..39bca99b1 100644
--- a/pystac/extensions/grid.py
+++ b/pystac/extensions/grid.py
@@ -3,7 +3,6 @@
 from __future__ import annotations
 
 import re
-import warnings
 from re import Pattern
 from typing import Any, Literal
 
@@ -92,6 +91,8 @@ def get_schema_uri(cls) -> str:
 
     @classmethod
     def get_schema_uris(cls) -> list[str]:
+        import warnings
+
         warnings.warn(
             "get_schema_uris is deprecated and will be removed in v2",
             DeprecationWarning,
diff --git a/pystac/extensions/item_assets.py b/pystac/extensions/item_assets.py
index 140207275..1743deed6 100644
--- a/pystac/extensions/item_assets.py
+++ b/pystac/extensions/item_assets.py
@@ -2,7 +2,6 @@
 
 from __future__ import annotations
 
-import warnings
 from typing import Any, Literal
 
 import pystac
@@ -27,6 +26,8 @@ class AssetDefinition(ItemAssetDefinition):
     """
 
     def __init__(cls, *args: Any, **kwargs: Any) -> None:
+        import warnings
+
         warnings.warn(
             (
                 "``AssetDefinition`` is deprecated. "
@@ -49,6 +50,8 @@ class ItemAssetsExtension(ExtensionManagementMixin[pystac.Collection]):
     collection: pystac.Collection
 
     def __init__(self, collection: pystac.Collection) -> None:
+        import warnings
+
         warnings.warn(
             (
                 "The ``item_assets`` extension is deprecated. "
diff --git a/pystac/extensions/projection.py b/pystac/extensions/projection.py
index 4adf3dae2..a0979c995 100644
--- a/pystac/extensions/projection.py
+++ b/pystac/extensions/projection.py
@@ -2,8 +2,6 @@
 
 from __future__ import annotations
 
-import json
-import warnings
 from collections.abc import Iterable
 from typing import (
     Any,
@@ -223,6 +221,8 @@ def crs_string(self) -> str | None:
         elif self.wkt2:
             return self.wkt2
         elif self.projjson:
+            import json
+
             return json.dumps(self.projjson)
         else:
             return None
@@ -321,6 +321,8 @@ def get_schema_uri(cls) -> str:
 
     @classmethod
     def get_schema_uris(cls) -> list[str]:
+        import warnings
+
         warnings.warn(
             "get_schema_uris is deprecated and will be removed in v2",
             DeprecationWarning,
diff --git a/pystac/extensions/raster.py b/pystac/extensions/raster.py
index ed239466f..0f59b45b6 100644
--- a/pystac/extensions/raster.py
+++ b/pystac/extensions/raster.py
@@ -2,7 +2,6 @@
 
 from __future__ import annotations
 
-import warnings
 from collections.abc import Iterable
 from typing import (
     Any,
@@ -716,6 +715,8 @@ def get_schema_uri(cls) -> str:
 
     @classmethod
     def get_schema_uris(cls) -> list[str]:
+        import warnings
+
         warnings.warn(
             "get_schema_uris is deprecated and will be removed in v2",
             DeprecationWarning,
diff --git a/pystac/extensions/scientific.py b/pystac/extensions/scientific.py
index b0d7821e7..9f6316b70 100644
--- a/pystac/extensions/scientific.py
+++ b/pystac/extensions/scientific.py
@@ -7,9 +7,7 @@
 
 from __future__ import annotations
 
-import copy
 from typing import Any, Generic, Literal, TypeVar, cast
-from urllib import parse
 
 import pystac
 from pystac.extensions.base import (
@@ -49,6 +47,8 @@ class ScientificRelType(StringEnum):
 
 def doi_to_url(doi: str) -> str:
     """Converts a DOI to the corresponding URL."""
+    from urllib import parse
+
     return DOI_URL_BASE + parse.quote(doi)
 
 
@@ -72,6 +72,8 @@ def __repr__(self) -> str:
         return f"<Publication doi={self.doi} target={self.citation}>"
 
     def to_dict(self) -> dict[str, str | None]:
+        import copy
+
         return copy.deepcopy({"doi": self.doi, "citation": self.citation})
 
     @staticmethod
diff --git a/pystac/extensions/version.py b/pystac/extensions/version.py
index b74d3f4c9..b1ad6016d 100644
--- a/pystac/extensions/version.py
+++ b/pystac/extensions/version.py
@@ -2,7 +2,6 @@
 
 from __future__ import annotations
 
-import warnings
 from collections.abc import Generator
 from contextlib import contextmanager
 from typing import (
@@ -437,6 +436,8 @@ def ignore_deprecated() -> Generator[None]:
     """Context manager for suppressing the :class:`pystac.DeprecatedWarning`
     when creating a deprecated :class:`~pystac.Item` or :class:`~pystac.Collection`
     from a dictionary."""
+    import warnings
+
     with warnings.catch_warnings():
         warnings.simplefilter("ignore", category=DeprecatedWarning)
         yield
diff --git a/pystac/item.py b/pystac/item.py
index f95c5a218..6a8bf4f53 100644
--- a/pystac/item.py
+++ b/pystac/item.py
@@ -1,6 +1,5 @@
 from __future__ import annotations
 
-import warnings
 from copy import copy, deepcopy
 from typing import TYPE_CHECKING, Any, TypeVar, cast
 
@@ -419,6 +418,8 @@ def from_dict(
         migrate: bool = True,
         preserve_dict: bool = True,
     ) -> T:
+        import warnings
+
         from pystac.extensions.version import ItemVersionExtension
 
         if preserve_dict:
diff --git a/pystac/item_assets.py b/pystac/item_assets.py
index 2260cdf0b..ab3a1fadb 100644
--- a/pystac/item_assets.py
+++ b/pystac/item_assets.py
@@ -6,7 +6,6 @@
 
 from __future__ import annotations
 
-from copy import deepcopy
 from typing import TYPE_CHECKING, Any
 
 import pystac
@@ -179,6 +178,8 @@ def roles(self, v: list[str] | None) -> None:
 
     def to_dict(self) -> dict[str, Any]:
         """Returns a dictionary representing this ``ItemAssetDefinition``."""
+        from copy import deepcopy
+
         return deepcopy(self.properties)
 
     def create_asset(self, href: str) -> pystac.Asset:
diff --git a/pystac/item_collection.py b/pystac/item_collection.py
index 5bf82c649..30634157d 100644
--- a/pystac/item_collection.py
+++ b/pystac/item_collection.py
@@ -1,8 +1,6 @@
 from __future__ import annotations
 
 from collections.abc import Collection, Iterable, Iterator
-from copy import deepcopy
-from html import escape
 from typing import (
     Any,
     TypeAlias,
@@ -11,7 +9,6 @@
 
 import pystac
 from pystac.errors import STACTypeError
-from pystac.html.jinja_env import get_jinja_env
 from pystac.serialization.identify import identify_stac_object_type
 from pystac.utils import HREF, is_absolute_href, make_absolute_href, make_posix_style
 
@@ -147,6 +144,10 @@ def to_dict(self, transform_hrefs: bool = False) -> dict[str, Any]:
         }
 
     def _repr_html_(self) -> str:
+        from html import escape
+
+        from pystac.html.jinja_env import get_jinja_env
+
         jinja_env = get_jinja_env()
         if jinja_env:
             template = jinja_env.get_template("JSON.jinja2")
@@ -158,6 +159,8 @@ def clone(self) -> ItemCollection:
         """Creates a clone of this instance. This clone is a deep copy; all
         :class:`~pystac.Item` instances are cloned and all additional top-level fields
         are deep copied."""
+        from copy import deepcopy
+
         return self.__class__(
             items=[item.clone() for item in self.items],
             extra_fields=deepcopy(self.extra_fields),
diff --git a/pystac/layout.py b/pystac/layout.py
index 88c963d12..b36668488 100644
--- a/pystac/layout.py
+++ b/pystac/layout.py
@@ -1,12 +1,9 @@
 from __future__ import annotations
 
-import os
 import posixpath
-import warnings
 from abc import ABC, abstractmethod
 from collections import OrderedDict
 from collections.abc import Callable
-from string import Formatter
 from typing import TYPE_CHECKING, Any
 
 import pystac
@@ -30,6 +27,8 @@ class TemplateError(Exception):
     """
 
     def __init__(self, *args, **kwargs) -> None:  # type: ignore
+        import warnings
+
         warnings.warn(
             message=(
                 "TemplateError in pystac.layout is deprecated and will be "
@@ -109,6 +108,8 @@ class LayoutTemplate:
     ITEM_TEMPLATE_VARS = ["date", "year", "month", "day", "collection"]
 
     def __init__(self, template: str, defaults: dict[str, str] | None = None) -> None:
+        from string import Formatter
+
         self.template = template
         self.defaults = defaults or {}
 
@@ -261,6 +262,8 @@ class HrefLayoutStrategy(ABC):
     def get_href(
         self, stac_object: STACObject, parent_dir: str, is_root: bool = False
     ) -> str:
+        import os
+
         if is_file_path(parent_dir):
             parent_dir = os.path.dirname(parent_dir)
 
diff --git a/pystac/link.py b/pystac/link.py
index 7b1cc4a0d..797f053e4 100644
--- a/pystac/link.py
+++ b/pystac/link.py
@@ -1,13 +1,10 @@
 from __future__ import annotations
 
 import os
-from copy import copy
-from html import escape
 from typing import TYPE_CHECKING, Any, TypeVar
 
 import pystac
 from pystac.errors import STACError
-from pystac.html.jinja_env import get_jinja_env
 from pystac.utils import (
     HREF as HREF,
 )
@@ -272,6 +269,10 @@ def __repr__(self) -> str:
         return f"<Link rel={self.rel} target={self.target}>"
 
     def _repr_html_(self) -> str:
+        from html import escape
+
+        from pystac.html.jinja_env import get_jinja_env
+
         jinja_env = get_jinja_env()
         if jinja_env:
             template = jinja_env.get_template("JSON.jinja2")
@@ -435,6 +436,8 @@ def from_dict(cls: type[L], d: dict[str, Any]) -> L:
         Returns:
             Link: Link instance constructed from the dict.
         """
+        from copy import copy
+
         d = copy(d)
         rel = d.pop("rel")
         href = d.pop("href")
diff --git a/pystac/provider.py b/pystac/provider.py
index 4152a28be..4db1f9174 100644
--- a/pystac/provider.py
+++ b/pystac/provider.py
@@ -1,7 +1,5 @@
-from html import escape
 from typing import Any
 
-from pystac.html.jinja_env import get_jinja_env
 from pystac.utils import StringEnum
 
 
@@ -73,6 +71,10 @@ def __eq__(self, o: object) -> bool:
         return self.to_dict() == o.to_dict()
 
     def _repr_html_(self) -> str:
+        from html import escape
+
+        from pystac.html.jinja_env import get_jinja_env
+
         jinja_env = get_jinja_env()
         if jinja_env:
             template = jinja_env.get_template("JSON.jinja2")
diff --git a/pystac/serialization/migrate.py b/pystac/serialization/migrate.py
index 8b1871bd2..4ed267437 100644
--- a/pystac/serialization/migrate.py
+++ b/pystac/serialization/migrate.py
@@ -1,7 +1,6 @@
 from __future__ import annotations
 
 from collections.abc import Callable
-from copy import deepcopy
 from typing import TYPE_CHECKING, Any
 
 import pystac
@@ -167,6 +166,8 @@ def migrate_to_latest(
         dict: A copy of the dict that is migrated to the latest version (the
         version that is pystac.version.STACVersion.DEFAULT_STAC_VERSION)
     """
+    from copy import deepcopy
+
     result = deepcopy(json_dict)
     version = info.version_range.latest_valid_version()
 
diff --git a/pystac/stac_io.py b/pystac/stac_io.py
index d194a8283..1436d7ffc 100644
--- a/pystac/stac_io.py
+++ b/pystac/stac_io.py
@@ -1,13 +1,10 @@
 from __future__ import annotations
 
 import json
-import logging
 import os
 from abc import ABC, abstractmethod
 from collections.abc import Callable
 from typing import TYPE_CHECKING, Any
-from urllib.error import HTTPError
-from urllib.request import Request, urlopen
 
 import pystac
 from pystac.serialization import (
@@ -37,9 +34,6 @@
     from pystac.stac_object import STACObject
 
 
-logger = logging.getLogger(__name__)
-
-
 class StacIO(ABC):
     _default_io: Callable[[], StacIO] | None = None
 
@@ -296,6 +290,11 @@ def read_text_from_href(self, href: str) -> str:
         """
         href_contents: str
         if _is_url(href):
+            import logging
+            from urllib.error import HTTPError
+            from urllib.request import Request, urlopen
+
+            logger = logging.getLogger(__name__)
             try:
                 logger.debug(f"GET {href} Headers: {self.headers}")
                 if HAS_URLLIB3:
@@ -451,6 +450,8 @@ def read_text_from_href(self, href: str) -> str:
                 href : The URI of the file to open.
             """
             if _is_url(href):
+                from urllib.error import HTTPError
+
                 # TODO provide a pooled StacIO to enable more efficient network
                 # access (probably named `PooledStacIO`).
                 http = PoolManager()
diff --git a/pystac/stac_object.py b/pystac/stac_object.py
index c95c83948..81545faf7 100644
--- a/pystac/stac_object.py
+++ b/pystac/stac_object.py
@@ -2,12 +2,10 @@
 
 from abc import ABC, abstractmethod
 from collections.abc import Callable, Iterable
-from html import escape
 from typing import TYPE_CHECKING, Any, TypeAlias, TypeVar, cast
 
 import pystac
 from pystac import STACError
-from pystac.html.jinja_env import get_jinja_env
 from pystac.link import Link
 from pystac.utils import (
     HREF,
@@ -584,6 +582,10 @@ def to_dict(
         raise NotImplementedError
 
     def _repr_html_(self) -> str:
+        from html import escape
+
+        from pystac.html.jinja_env import get_jinja_env
+
         jinja_env = get_jinja_env()
         if jinja_env:
             template = jinja_env.get_template("JSON.jinja2")
diff --git a/pystac/summaries.py b/pystac/summaries.py
index 1e3998008..c3b9715bf 100644
--- a/pystac/summaries.py
+++ b/pystac/summaries.py
@@ -1,11 +1,7 @@
 from __future__ import annotations
 
-import importlib.resources
-import json
-import numbers
 from abc import abstractmethod
 from collections.abc import Iterable
-from copy import deepcopy
 from enum import Enum
 from functools import lru_cache
 from typing import (
@@ -100,6 +96,9 @@ def __repr__(self) -> str:
 @lru_cache(maxsize=None)
 def _get_fields_json(url: str | None) -> dict[str, Any]:
     if url is None:
+        import importlib.resources
+        import json
+
         # Every time pystac is released this file gets pulled from
         # https://cdn.jsdelivr.net/npm/@radiantearth/stac-fields/fields-normalized.json
         jsonfields: dict[str, Any] = json.loads(
@@ -170,6 +169,8 @@ def _set_field_definitions(self, fields: dict[str, Any]) -> None:
                 self.summaryfields[name] = strategy
 
     def _update_with_item(self, summaries: Summaries, item: Item) -> None:
+        import numbers
+
         for k, v in item.properties.items():
             if k in self.summaryfields:
                 strategy = self.summaryfields[k]
@@ -310,6 +311,8 @@ def clone(self) -> Summaries:
         Returns:
             Summaries: The clone of this object
         """
+        from copy import deepcopy
+
         cls = self.__class__
         summaries = cls(summaries=deepcopy(self._summaries), maxcount=self.maxcount)
         summaries.lists = deepcopy(self.lists)
diff --git a/pystac/utils.py b/pystac/utils.py
index 4225fd1d5..623ea4889 100644
--- a/pystac/utils.py
+++ b/pystac/utils.py
@@ -2,7 +2,6 @@
 
 import os
 import posixpath
-import warnings
 from collections.abc import Callable
 from datetime import datetime, timezone
 from enum import Enum
@@ -15,8 +14,6 @@
 from urllib.parse import ParseResult as URLParseResult
 from urllib.parse import urljoin, urlparse, urlunparse
 
-import dateutil.parser
-
 from pystac.errors import RequiredPropertyMissing
 
 #: HREF string or path-like object.
@@ -132,6 +129,8 @@ def from_parsed_uri(parsed_uri: URLParseResult) -> JoinType:
         Returns:
             JoinType : The join type for the URI.
         """
+        import warnings
+
         warnings.warn(
             message=(
                 "from_parsed_uri is deprecated and will be removed in pystac "
@@ -166,6 +165,8 @@ def join_path_or_url(join_type: JoinType, *args: str) -> str:
     Returns:
         str : The joined path
     """
+    import warnings
+
     warnings.warn(
         message=(
             "join_path_or_url is deprecated and will be removed in pystac "
@@ -432,6 +433,8 @@ def str_to_datetime(s: str) -> datetime:
     Returns:
         str: The :class:`datetime.datetime` represented the by the string.
     """
+    import dateutil.parser
+
     return dateutil.parser.isoparse(s)
 
 
diff --git a/pystac/validation/__init__.py b/pystac/validation/__init__.py
index 4b9be8269..f48629c62 100644
--- a/pystac/validation/__init__.py
+++ b/pystac/validation/__init__.py
@@ -1,6 +1,5 @@
 from __future__ import annotations
 
-import warnings
 from collections.abc import Iterable, Mapping
 from typing import TYPE_CHECKING, Any, cast
 
@@ -164,6 +163,8 @@ def validate_all(
         stac_io = pystac.StacIO.default()
 
     if isinstance(stac_object, dict):
+        import warnings
+
         warnings.warn(
             "validating a STAC object as a dict is deprecated;"
             " use validate_all_dict instead",
diff --git a/pystac/validation/local_validator.py b/pystac/validation/local_validator.py
index 88f2a7447..93a7e40aa 100644
--- a/pystac/validation/local_validator.py
+++ b/pystac/validation/local_validator.py
@@ -1,10 +1,7 @@
-import importlib.resources
 import json
-import warnings
 from typing import Any, cast
 
 from jsonschema import Draft7Validator, ValidationError
-from referencing import Registry, Resource
 
 from pystac.errors import STACLocalValidationError
 from pystac.version import STACVersion
@@ -13,6 +10,8 @@
 
 
 def _read_schema(file_name: str) -> dict[str, Any]:
+    import importlib.resources
+
     with (
         importlib.resources.files("pystac.validation.jsonschemas")
         .joinpath(file_name)
@@ -73,6 +72,8 @@ def get_local_schema_cache() -> dict[str, dict[str, Any]]:
 
 def __getattr__(name: str) -> Any:
     if name in deprecated_names:
+        import warnings
+
         warnings.warn(f"{name} is deprecated and will be removed in v2.", FutureWarning)
         return globals()[f"_deprecated_{name}"]
     raise AttributeError(f"module {__name__} has no attribute {name}")
@@ -81,6 +82,8 @@ def __getattr__(name: str) -> Any:
 class LocalValidator:
     def __init__(self) -> None:
         """DEPRECATED"""
+        import warnings
+
         warnings.warn(
             "``LocalValidator`` is deprecated and will be removed in v2.",
             DeprecationWarning,
@@ -88,6 +91,8 @@ def __init__(self) -> None:
         self.schema_cache = get_local_schema_cache()
 
     def registry(self) -> Any:
+        from referencing import Registry, Resource
+
         return Registry().with_resources(
             [(k, Resource.from_contents(v)) for k, v in self.schema_cache.items()]
         )
diff --git a/pystac/version.py b/pystac/version.py
index 2e5161947..1c54dcd94 100644
--- a/pystac/version.py
+++ b/pystac/version.py
@@ -1,5 +1,3 @@
-import os
-
 __version__ = "1.14.1"
 """Library version"""
 
@@ -21,6 +19,8 @@ def get_stac_version(cls) -> str:
         if cls._override_version is not None:
             return cls._override_version
 
+        import os
+
         env_version = os.environ.get(cls.OVERRIDE_VERSION_ENV_VAR)
         if env_version is not None:
             return env_version