diff --git a/packages/gapic-generator/tests/integration/goldens/asset/google/cloud/asset_v1/__init__.py b/packages/gapic-generator/tests/integration/goldens/asset/google/cloud/asset_v1/__init__.py
index c4cff9be0634..589ca0f7adb9 100755
--- a/packages/gapic-generator/tests/integration/goldens/asset/google/cloud/asset_v1/__init__.py
+++ b/packages/gapic-generator/tests/integration/goldens/asset/google/cloud/asset_v1/__init__.py
@@ -118,8 +118,8 @@
 from .types.assets import TimeWindow
 from .types.assets import VersionedResource
 
-api_core.check_python_version("google.cloud.asset_v1")
-api_core.check_dependency_versions("google.cloud.asset_v1")
+api_core.check_python_version("")
+api_core.check_dependency_versions("")
 
 __all__ = (
     'AssetServiceAsyncClient',
diff --git a/packages/gapic-generator/tests/integration/goldens/credentials/google/iam/credentials_v1/__init__.py b/packages/gapic-generator/tests/integration/goldens/credentials/google/iam/credentials_v1/__init__.py
index 9c0c65db39c0..f677d1815122 100755
--- a/packages/gapic-generator/tests/integration/goldens/credentials/google/iam/credentials_v1/__init__.py
+++ b/packages/gapic-generator/tests/integration/goldens/credentials/google/iam/credentials_v1/__init__.py
@@ -44,8 +44,8 @@
 from .types.common import SignJwtRequest
 from .types.common import SignJwtResponse
 
-api_core.check_python_version("google.iam.credentials_v1")
-api_core.check_dependency_versions("google.iam.credentials_v1")
+api_core.check_python_version("")
+api_core.check_dependency_versions("")
 
 __all__ = (
     'IAMCredentialsAsyncClient',
diff --git a/packages/gapic-generator/tests/integration/goldens/logging/google/cloud/logging_v2/__init__.py b/packages/gapic-generator/tests/integration/goldens/logging/google/cloud/logging_v2/__init__.py
index 5e2f12d53746..62609e4635cd 100755
--- a/packages/gapic-generator/tests/integration/goldens/logging/google/cloud/logging_v2/__init__.py
+++ b/packages/gapic-generator/tests/integration/goldens/logging/google/cloud/logging_v2/__init__.py
@@ -120,8 +120,8 @@
 from .types.logging_metrics import LogMetric
 from .types.logging_metrics import UpdateLogMetricRequest
 
-api_core.check_python_version("google.cloud.logging_v2")
-api_core.check_dependency_versions("google.cloud.logging_v2")
+api_core.check_python_version("")
+api_core.check_dependency_versions("")
 
 __all__ = (
     'ConfigServiceV2AsyncClient',
diff --git a/packages/gapic-generator/tests/integration/goldens/logging_internal/google/cloud/logging_v2/__init__.py b/packages/gapic-generator/tests/integration/goldens/logging_internal/google/cloud/logging_v2/__init__.py
index b58fac5882bb..e138052ae3de 100755
--- a/packages/gapic-generator/tests/integration/goldens/logging_internal/google/cloud/logging_v2/__init__.py
+++ b/packages/gapic-generator/tests/integration/goldens/logging_internal/google/cloud/logging_v2/__init__.py
@@ -120,8 +120,8 @@
 from .types.logging_metrics import LogMetric
 from .types.logging_metrics import UpdateLogMetricRequest
 
-api_core.check_python_version("google.cloud.logging_v2")
-api_core.check_dependency_versions("google.cloud.logging_v2")
+api_core.check_python_version("")
+api_core.check_dependency_versions("")
 
 __all__ = (
     'BaseConfigServiceV2AsyncClient',
diff --git a/packages/gapic-generator/tests/integration/goldens/redis_selective/google/cloud/redis_v1/__init__.py b/packages/gapic-generator/tests/integration/goldens/redis_selective/google/cloud/redis_v1/__init__.py
index 1b8d17cc75ca..7b84c8338fd3 100755
--- a/packages/gapic-generator/tests/integration/goldens/redis_selective/google/cloud/redis_v1/__init__.py
+++ b/packages/gapic-generator/tests/integration/goldens/redis_selective/google/cloud/redis_v1/__init__.py
@@ -55,8 +55,8 @@
 from .types.cloud_redis import WeeklyMaintenanceWindow
 from .types.cloud_redis import ZoneMetadata
 
-api_core.check_python_version("google.cloud.redis_v1")
-api_core.check_dependency_versions("google.cloud.redis_v1")
+api_core.check_python_version("")
+api_core.check_dependency_versions("")
 
 __all__ = (
     'CloudRedisAsyncClient',
diff --git a/packages/gapic-generator/tests/integration/goldens/storagebatchoperations/google/cloud/storagebatchoperations_v1/__init__.py b/packages/gapic-generator/tests/integration/goldens/storagebatchoperations/google/cloud/storagebatchoperations_v1/__init__.py
index 08bda73fa39f..7c5150513e9b 100755
--- a/packages/gapic-generator/tests/integration/goldens/storagebatchoperations/google/cloud/storagebatchoperations_v1/__init__.py
+++ b/packages/gapic-generator/tests/integration/goldens/storagebatchoperations/google/cloud/storagebatchoperations_v1/__init__.py
@@ -64,8 +64,8 @@
 from .types.storage_batch_operations_types import RewriteObject
 from .types.storage_batch_operations_types import UpdateObjectCustomContext
 
-api_core.check_python_version("google.cloud.storagebatchoperations_v1")
-api_core.check_dependency_versions("google.cloud.storagebatchoperations_v1")
+api_core.check_python_version("")
+api_core.check_dependency_versions("")
 
 __all__ = (
     'StorageBatchOperationsAsyncClient',
diff --git a/packages/google-api-core/google/api_core/_python_package_support.py b/packages/google-api-core/google/api_core/_python_package_support.py
index a6c35d8c1804..25aa4cd322c8 100644
--- a/packages/google-api-core/google/api_core/_python_package_support.py
+++ b/packages/google-api-core/google/api_core/_python_package_support.py
@@ -30,14 +30,37 @@
 # about deprecated and unsupported versions.
 DependencyConstraint = namedtuple(
     "DependencyConstraint",
-    ["package_name", "minimum_fully_supported_version", "recommended_version"],
+    [
+        "package_name",
+        "minimum_fully_supported_version",
+        "recommended_version",
+        "message_template",
+    ],
+    defaults=(None, None),
 )
+
+PQC_GRPC_WARNING_TEMPLATE = (
+    "Package {consumer_package} depends on {dependency_package}, currently installed at version {version_used_string}. "
+    "grpcio < 1.83.0 does not support Post-Quantum Cryptography (PQC). "
+    "Support for non-PQC environments is deprecated. In October 2026, "
+    "Google Cloud Python packages will raise their minimum requirements "
+    "(including google-api-core, grpcio, and grpcio-status) to enforce grpcio >= 1.83.0. "
+    "For more details on Google Cloud's post-quantum security migration, visit: "
+    "https://cloud.google.com/security/resources/post-quantum-cryptography"
+)
+
 _PACKAGE_DEPENDENCY_WARNINGS = [
     DependencyConstraint(
         "google.protobuf",
         minimum_fully_supported_version="6.33.5",
         recommended_version="6.x",
-    )
+    ),
+    DependencyConstraint(
+        "grpcio",
+        minimum_fully_supported_version="1.83.0",
+        recommended_version="1.83.x",
+        message_template=PQC_GRPC_WARNING_TEMPLATE,
+    ),
 ]
 
 
@@ -50,8 +73,8 @@
 def parse_version_to_tuple(version_string: str) -> ParsedVersion:
     """Safely converts a semantic version string to a comparable tuple of integers.
 
-    Example: "6.33.5" -> (6, 33, 5)
-    Ignores non-numeric parts and handles common version formats.
+    Example: "6.33.5" -> (6, 33, 5), "1.83.1rc1" -> (1, 83, 1)
+    Parses leading digits of each component to correctly handle pre-releases.
 
     Args:
         version_string: Version string in the format "x.y.z" or "x.y.z<suffix>"
@@ -61,12 +84,14 @@ def parse_version_to_tuple(version_string: str) -> ParsedVersion:
     """
     parts = []
     for part in version_string.split("."):
-        try:
-            parts.append(int(part))
-        except ValueError:
-            # If it's a non-numeric part (e.g., '1.0.0b1' -> 'b1'), stop here.
-            # This is a simplification compared to 'packaging.parse_version', but sufficient
-            # for comparing strictly numeric semantic versions.
+        digits = ""
+        for c in part:
+            if not c.isdigit():
+                break
+            digits += c
+        if digits:
+            parts.append(int(digits))
+        else:
             break
     return tuple(parts)
 
@@ -162,7 +187,7 @@ def warn_deprecation_for_versions_less_than(
         ) = _get_distribution_and_import_packages(consumer_import_package)
 
         recommendation = (
-            " (we recommend {recommended_version})" if recommended_version else ""
+            f" (we recommend {recommended_version})" if recommended_version else ""
         )
         message_template = message_template or _flatten_message(
             """
@@ -222,4 +247,5 @@ def check_dependency_versions(
             package_info.package_name,
             package_info.minimum_fully_supported_version,
             recommended_version=package_info.recommended_version,
+            message_template=package_info.message_template,
         )
diff --git a/packages/google-api-core/tests/unit/test_python_package_support.py b/packages/google-api-core/tests/unit/test_python_package_support.py
index 42e8de673dea..76ed6eed837b 100644
--- a/packages/google-api-core/tests/unit/test_python_package_support.py
+++ b/packages/google-api-core/tests/unit/test_python_package_support.py
@@ -18,6 +18,7 @@
 import pytest
 
 from google.api_core._python_package_support import (
+    PQC_GRPC_WARNING_TEMPLATE,
     DependencyConstraint,
     DependencyVersion,
     check_dependency_versions,
@@ -37,14 +38,20 @@ def test_get_dependency_version(mocker, version_string_to_test):
         parse_version_to_tuple(version_string_to_test), version_string_to_test
     )
     assert get_dependency_version("some-package") == expected
-
     mock_importlib.assert_called_once_with("some-package")
 
     # Test package not found
-    mock_importlib.side_effect = ImportError
+    mock_importlib.side_effect = Exception
     assert get_dependency_version("not-a-package") == DependencyVersion(None, "--")
 
 
+def test_parse_version_to_tuple_prerelease():
+    """Test parse_version_to_tuple with pre-release versions."""
+    assert parse_version_to_tuple("1.83.1rc1") == (1, 83, 1)
+    assert parse_version_to_tuple("1.83.0dev0") == (1, 83, 0)
+    assert parse_version_to_tuple("6.33.5b2") == (6, 33, 5)
+
+
 @patch("google.api_core._python_package_support._get_distribution_and_import_packages")
 @patch("google.api_core._python_package_support.get_dependency_version")
 def test_warn_deprecation_for_versions_less_than(mock_get_version, mock_get_packages):
@@ -125,8 +132,40 @@ def test_check_dependency_versions_with_custom_warnings(mock_warn):
 
     assert mock_warn.call_count == 2
     mock_warn.assert_any_call(
-        "my-consumer", "pkg1", "1.0.0", recommended_version="2.0.0"
+        "my-consumer",
+        "pkg1",
+        "1.0.0",
+        recommended_version="2.0.0",
+        message_template=None,
+    )
+    mock_warn.assert_any_call(
+        "my-consumer",
+        "pkg2",
+        "2.0.0",
+        recommended_version="3.0.0",
+        message_template=None,
+    )
+
+
+@patch(
+    "google.api_core._python_package_support.warn_deprecation_for_versions_less_than"
+)
+def test_check_dependency_versions_default(mock_warn):
+    """Test check_dependency_versions with default package dependency warnings."""
+    check_dependency_versions("my-consumer")
+
+    assert mock_warn.call_count == 2
+    mock_warn.assert_any_call(
+        "my-consumer",
+        "google.protobuf",
+        "6.33.5",
+        recommended_version="6.x",
+        message_template=None,
     )
     mock_warn.assert_any_call(
-        "my-consumer", "pkg2", "2.0.0", recommended_version="3.0.0"
+        "my-consumer",
+        "grpcio",
+        "1.83.0",
+        recommended_version="1.83.x",
+        message_template=PQC_GRPC_WARNING_TEMPLATE,
     )
diff --git a/packages/google-auth/google/auth/_helpers.py b/packages/google-auth/google/auth/_helpers.py
index 86c48c1e525c..3abc0b6cc9fd 100644
--- a/packages/google-auth/google/auth/_helpers.py
+++ b/packages/google-auth/google/auth/_helpers.py
@@ -534,3 +534,19 @@ def response_log(logger: logging.Logger, response: Any) -> None:
     if is_logging_enabled(logger):
         json_response = _parse_response(response)
         _response_log_base(logger, json_response)
+
+
+def _parse_version_to_tuple(version_string):
+    """Safely converts a semantic version string to a comparable tuple of integers."""
+    parts = []
+    for part in version_string.split("."):
+        digits = ""
+        for c in part:
+            if not c.isdigit():
+                break
+            digits += c
+        if digits:
+            parts.append(int(digits))
+        else:
+            break
+    return tuple(parts)
diff --git a/packages/google-auth/google/auth/transport/grpc.py b/packages/google-auth/google/auth/transport/grpc.py
index 5930a07f1d08..13e8077e724c 100644
--- a/packages/google-auth/google/auth/transport/grpc.py
+++ b/packages/google-auth/google/auth/transport/grpc.py
@@ -18,6 +18,7 @@
 
 import logging
 
+from google.auth import _helpers
 from google.auth import exceptions
 from google.auth.transport import _mtls_helper
 from google.auth.transport import mtls
@@ -30,6 +31,25 @@
         "gRPC is not installed from please install the grpcio package to use the gRPC transport."
     ) from caught_exc
 
+
+try:
+    import importlib.metadata
+    import warnings
+
+    _grpc_ver_str = importlib.metadata.version("grpcio")
+    if _helpers._parse_version_to_tuple(_grpc_ver_str) < (1, 83, 0):
+        warnings.warn(
+            "grpcio < 1.83.0 does not support Post-Quantum Cryptography (PQC). "
+            "Support for non-PQC environments is deprecated. In October 2026, "
+            "google-auth will raise its minimum requirements "
+            "to enforce grpcio >= 1.83.0. "
+            "For more details on Google Cloud's post-quantum security migration, visit: "
+            "https://cloud.google.com/security/resources/post-quantum-cryptography",
+            FutureWarning,
+        )
+except Exception:
+    pass
+
 _LOGGER = logging.getLogger(__name__)
 
 
diff --git a/packages/google-auth/tests/test__helpers.py b/packages/google-auth/tests/test__helpers.py
index e2d8e7b20c03..ad2de3eeca6e 100644
--- a/packages/google-auth/tests/test__helpers.py
+++ b/packages/google-auth/tests/test__helpers.py
@@ -697,3 +697,10 @@ def test_out_of_range(self):
         with pytest.raises((OverflowError, OSError, ValueError)):
             # Large enough to fail on most systems (Year 300,000+)
             _helpers.utcfromtimestamp(9999999999999)
+
+
+def test_parse_version_to_tuple():
+    assert _helpers._parse_version_to_tuple("1.83.0") == (1, 83, 0)
+    assert _helpers._parse_version_to_tuple("1.83.1rc1") == (1, 83, 1)
+    assert _helpers._parse_version_to_tuple("1.83.0dev0") == (1, 83, 0)
+    assert _helpers._parse_version_to_tuple("2.0") == (2, 0)
diff --git a/packages/google-cloud-bigquery/google/cloud/bigquery/__init__.py b/packages/google-cloud-bigquery/google/cloud/bigquery/__init__.py
index fa03156e2e26..fd0a81c9bf9a 100644
--- a/packages/google-cloud-bigquery/google/cloud/bigquery/__init__.py
+++ b/packages/google-cloud-bigquery/google/cloud/bigquery/__init__.py
@@ -34,6 +34,10 @@
 
 __version__ = bigquery_version.__version__
 
+import google.api_core as api_core
+
+api_core.check_python_version("google.cloud.bigquery")
+api_core.check_dependency_versions("google.cloud.bigquery")
 from google.cloud.bigquery.client import Client
 from google.cloud.bigquery.dataset import AccessEntry
 from google.cloud.bigquery.dataset import Dataset
@@ -123,14 +127,6 @@
 except ImportError:
     bigquery_magics = None
 
-if sys.version_info < (3, 10):  # pragma: NO COVER
-    warnings.warn(
-        "The python-bigquery library no longer supports Python <= 3.9. "
-        f"Your Python version is {sys.version_info.major}.{sys.version_info.minor}.{sys.version_info.micro}. We "
-        "recommend that you update soon to ensure ongoing support. For "
-        "more details, see: [Google Cloud Client Libraries Supported Python Versions policy](https://cloud.google.com/python/docs/supported-python-versions)",
-        FutureWarning,
-    )
 
 __all__ = [
     "__version__",
diff --git a/packages/google-cloud-bigquery/tests/unit/test__helpers.py b/packages/google-cloud-bigquery/tests/unit/test__helpers.py
index 4e53236e39e7..861954fd6269 100644
--- a/packages/google-cloud-bigquery/tests/unit/test__helpers.py
+++ b/packages/google-cloud-bigquery/tests/unit/test__helpers.py
@@ -1214,3 +1214,4 @@ def test__valid_isinstance_or_raise(self, value, dtype, none_allowed, expected):
     def test__invalid_isinstance_or_raise(self, value, dtype, none_allowed, expected):
         with expected:
             _isinstance_or_raise(value, dtype, none_allowed=none_allowed)
+
diff --git a/packages/google-cloud-ndb/google/cloud/ndb/__init__.py b/packages/google-cloud-ndb/google/cloud/ndb/__init__.py
index 153ff9d1db7c..291d2a6aa074 100644
--- a/packages/google-cloud-ndb/google/cloud/ndb/__init__.py
+++ b/packages/google-cloud-ndb/google/cloud/ndb/__init__.py
@@ -21,8 +21,15 @@
 .. autodata:: __all__
 """
 
+from google.cloud.ndb import utils
 from google.cloud.ndb import version
 
+
+import google.api_core as api_core
+
+api_core.check_python_version("google.cloud.ndb")
+api_core.check_dependency_versions("google.cloud.ndb")
+
 __version__: str = version.__version__
 
 from google.cloud.ndb._datastore_api import EVENTUAL, EVENTUAL_CONSISTENCY, STRONG
diff --git a/packages/google-cloud-ndb/google/cloud/ndb/utils.py b/packages/google-cloud-ndb/google/cloud/ndb/utils.py
index aecf861cd52c..833c4c31c6e3 100644
--- a/packages/google-cloud-ndb/google/cloud/ndb/utils.py
+++ b/packages/google-cloud-ndb/google/cloud/ndb/utils.py
@@ -163,3 +163,4 @@ def tweak_logging(*args, **kwargs):
 def wrapping(*args, **kwargs):
     """Use functools.wraps instead"""
     raise NotImplementedError
+
diff --git a/packages/google-cloud-ndb/tests/unit/test_utils.py b/packages/google-cloud-ndb/tests/unit/test_utils.py
index 571aa5ada0ed..3041414a90d6 100644
--- a/packages/google-cloud-ndb/tests/unit/test_utils.py
+++ b/packages/google-cloud-ndb/tests/unit/test_utils.py
@@ -133,3 +133,4 @@ def test_tweak_logging():
 def test_wrapping():
     with pytest.raises(NotImplementedError):
         utils.wrapping()
+