diff --git a/gapic/templates/setup.py.j2 b/gapic/templates/setup.py.j2
index 831f5d0f31..dcff94f973 100644
--- a/gapic/templates/setup.py.j2
+++ b/gapic/templates/setup.py.j2
@@ -33,7 +33,7 @@ else:
     release_status = "Development Status :: 5 - Production/Stable"
 
 dependencies = [
-    "google-api-core[grpc] >= 2.11.0, <3.0.0",
+    "google-api-core[grpc] >= 2.17.1, <3.0.0",
     # Exclude incompatible versions of `google-auth`
     # See https://github.com/googleapis/google-cloud-python/issues/12364
     "google-auth >= 2.14.1, <3.0.0,!=2.24.0,!=2.25.0",
diff --git a/gapic/templates/testing/constraints-3.9-async-rest.txt.j2 b/gapic/templates/testing/constraints-3.9-async-rest.txt.j2
new file mode 100644
index 0000000000..96b0ff860e
--- /dev/null
+++ b/gapic/templates/testing/constraints-3.9-async-rest.txt.j2
@@ -0,0 +1,28 @@
+{% set rest_async_io_enabled = api.all_library_settings[api.naming.proto_package].python_settings.experimental_features.rest_async_io_enabled %}
+{% if rest_async_io_enabled %}
+# -*- coding: utf-8 -*-
+{% from '_pypi_packages.j2' import pypi_packages %}
+# This constraints file is used to check that lower bounds
+# are correct in setup.py
+# List all library dependencies and extras in this file,
+# pinning their versions to their lower bounds.
+# For example, if setup.py has "google-cloud-foo >= 1.14.0, < 2.0.0",
+# then this file should have google-cloud-foo==1.14.0
+google-api-core==2.21.0
+google-auth==2.35.0
+{% if api.requires_package(("google", "iam", "v1")) or api.naming.warehouse_package_name == 'google-fragment' %}
+grpcio==1.44.0  # from grpc-google-iam-v1
+{% else %}
+grpcio==1.33.2  # from google-api-core
+{% endif %}
+proto-plus==1.22.3
+protobuf==4.25.8
+{% for package_tuple, package_info in pypi_packages.items() %}
+{# Quick check to make sure `package_info.package_name` is not the package being generated so we don't circularly include this package in its own constraints file. #}
+{% if api.naming.warehouse_package_name != package_info.package_name %}
+{% if api.requires_package(package_tuple) %}
+{{ package_info.package_name }}=={{ package_info.lower_bound }}
+{% endif %}
+{% endif %}
+{% endfor %}
+{% endif %}
\ No newline at end of file
diff --git a/gapic/templates/testing/constraints-3.9.txt.j2 b/gapic/templates/testing/constraints-3.9.txt.j2
index 59cd2c38c8..f2d6fa3f6a 100644
--- a/gapic/templates/testing/constraints-3.9.txt.j2
+++ b/gapic/templates/testing/constraints-3.9.txt.j2
@@ -6,10 +6,13 @@
 # pinning their versions to their lower bounds.
 # For example, if setup.py has "google-cloud-foo >= 1.14.0, < 2.0.0",
 # then this file should have google-cloud-foo==1.14.0
-google-api-core==2.21.0
-google-auth==2.35.0
-# TODO(https://github.com/googleapis/gapic-generator-python/issues/2453)
-# Add the minimum supported version of grpcio to constraints files
+google-api-core==2.17.1
+google-auth==2.14.1
+{% if api.requires_package(("google", "iam", "v1")) or api.naming.warehouse_package_name == 'google-fragment' %}
+grpcio==1.44.0  # from grpc-google-iam-v1
+{% else %}
+grpcio==1.33.2  # from google-api-core
+{% endif %}
 proto-plus==1.22.3
 protobuf==4.25.8
 {% for package_tuple, package_info in pypi_packages.items() %}
diff --git a/noxfile.py b/noxfile.py
index 649de4e7f0..57d6ba010e 100644
--- a/noxfile.py
+++ b/noxfile.py
@@ -357,21 +357,21 @@ def showcase_library(
             constraints_path = str(
                 f"{tmp_dir}/testing/constraints-{session.python}.txt"
             )
-            # Install the library with a constraints file.
-            session.install(
-                "-e",
-                tmp_dir + ("[async_rest]" if rest_async_io_enabled else ""),
-                "-r",
-                constraints_path,
-            )
-            # Exclude `google-auth==2.40.0` which contains a regression
-            # https://github.com/googleapis/gapic-generator-python/issues/2385
-            session.install(
-                "--no-cache-dir",
-                "--force-reinstall",
-                "--upgrade",
-                "google-auth[aiohttp]!=2.40.0",
-            )
+            extras = ""
+            if rest_async_io_enabled:
+                async_rest_constraints_path = str(
+                    f"{tmp_dir}/testing/constraints-{session.python}-async-rest.txt"
+                )
+                if os.path.exists(async_rest_constraints_path):
+                    # use async-rest constraints if available
+                    constraints_path = async_rest_constraints_path
+                else:
+                    session.log(
+                        f"{async_rest_constraints_path} not found. Using base constraints file"
+                    )
+                extras = "[async_rest]"
+
+            session.install("-e", f"{tmp_dir}{extras}", "-r", constraints_path)
         else:
             # The ads templates do not have constraints files.
             # See https://github.com/googleapis/gapic-generator-python/issues/1788
diff --git a/tests/integration/goldens/asset/setup.py b/tests/integration/goldens/asset/setup.py
index 7f5523e3bf..165a48972f 100755
--- a/tests/integration/goldens/asset/setup.py
+++ b/tests/integration/goldens/asset/setup.py
@@ -39,7 +39,7 @@
     release_status = "Development Status :: 5 - Production/Stable"
 
 dependencies = [
-    "google-api-core[grpc] >= 2.11.0, <3.0.0",
+    "google-api-core[grpc] >= 2.17.1, <3.0.0",
     # Exclude incompatible versions of `google-auth`
     # See https://github.com/googleapis/google-cloud-python/issues/12364
     "google-auth >= 2.14.1, <3.0.0,!=2.24.0,!=2.25.0",
diff --git a/tests/integration/goldens/asset/testing/constraints-3.9.txt b/tests/integration/goldens/asset/testing/constraints-3.9.txt
index 66ee36eb25..8333ac3bda 100755
--- a/tests/integration/goldens/asset/testing/constraints-3.9.txt
+++ b/tests/integration/goldens/asset/testing/constraints-3.9.txt
@@ -5,10 +5,9 @@
 # pinning their versions to their lower bounds.
 # For example, if setup.py has "google-cloud-foo >= 1.14.0, < 2.0.0",
 # then this file should have google-cloud-foo==1.14.0
-google-api-core==2.21.0
-google-auth==2.35.0
-# TODO(https://github.com/googleapis/gapic-generator-python/issues/2453)
-# Add the minimum supported version of grpcio to constraints files
+google-api-core==2.17.1
+google-auth==2.14.1
+grpcio==1.44.0  # from grpc-google-iam-v1
 proto-plus==1.22.3
 protobuf==4.25.8
 google-cloud-access-context-manager==0.2.0
diff --git a/tests/integration/goldens/credentials/setup.py b/tests/integration/goldens/credentials/setup.py
index 8da6aed1dd..37422f10cc 100755
--- a/tests/integration/goldens/credentials/setup.py
+++ b/tests/integration/goldens/credentials/setup.py
@@ -39,7 +39,7 @@
     release_status = "Development Status :: 5 - Production/Stable"
 
 dependencies = [
-    "google-api-core[grpc] >= 2.11.0, <3.0.0",
+    "google-api-core[grpc] >= 2.17.1, <3.0.0",
     # Exclude incompatible versions of `google-auth`
     # See https://github.com/googleapis/google-cloud-python/issues/12364
     "google-auth >= 2.14.1, <3.0.0,!=2.24.0,!=2.25.0",
diff --git a/tests/integration/goldens/credentials/testing/constraints-3.9.txt b/tests/integration/goldens/credentials/testing/constraints-3.9.txt
index ac3833d41b..d5ce286e09 100755
--- a/tests/integration/goldens/credentials/testing/constraints-3.9.txt
+++ b/tests/integration/goldens/credentials/testing/constraints-3.9.txt
@@ -5,9 +5,8 @@
 # pinning their versions to their lower bounds.
 # For example, if setup.py has "google-cloud-foo >= 1.14.0, < 2.0.0",
 # then this file should have google-cloud-foo==1.14.0
-google-api-core==2.21.0
-google-auth==2.35.0
-# TODO(https://github.com/googleapis/gapic-generator-python/issues/2453)
-# Add the minimum supported version of grpcio to constraints files
+google-api-core==2.17.1
+google-auth==2.14.1
+grpcio==1.33.2  # from google-api-core
 proto-plus==1.22.3
 protobuf==4.25.8
diff --git a/tests/integration/goldens/eventarc/setup.py b/tests/integration/goldens/eventarc/setup.py
index cbb2177568..946de9f043 100755
--- a/tests/integration/goldens/eventarc/setup.py
+++ b/tests/integration/goldens/eventarc/setup.py
@@ -39,7 +39,7 @@
     release_status = "Development Status :: 5 - Production/Stable"
 
 dependencies = [
-    "google-api-core[grpc] >= 2.11.0, <3.0.0",
+    "google-api-core[grpc] >= 2.17.1, <3.0.0",
     # Exclude incompatible versions of `google-auth`
     # See https://github.com/googleapis/google-cloud-python/issues/12364
     "google-auth >= 2.14.1, <3.0.0,!=2.24.0,!=2.25.0",
diff --git a/tests/integration/goldens/eventarc/testing/constraints-3.9.txt b/tests/integration/goldens/eventarc/testing/constraints-3.9.txt
index dcb9a9b3d8..faecbe2655 100755
--- a/tests/integration/goldens/eventarc/testing/constraints-3.9.txt
+++ b/tests/integration/goldens/eventarc/testing/constraints-3.9.txt
@@ -5,10 +5,9 @@
 # pinning their versions to their lower bounds.
 # For example, if setup.py has "google-cloud-foo >= 1.14.0, < 2.0.0",
 # then this file should have google-cloud-foo==1.14.0
-google-api-core==2.21.0
-google-auth==2.35.0
-# TODO(https://github.com/googleapis/gapic-generator-python/issues/2453)
-# Add the minimum supported version of grpcio to constraints files
+google-api-core==2.17.1
+google-auth==2.14.1
+grpcio==1.44.0  # from grpc-google-iam-v1
 proto-plus==1.22.3
 protobuf==4.25.8
 grpc-google-iam-v1==0.14.0
diff --git a/tests/integration/goldens/logging/setup.py b/tests/integration/goldens/logging/setup.py
index 0b99458443..2f1b079f1b 100755
--- a/tests/integration/goldens/logging/setup.py
+++ b/tests/integration/goldens/logging/setup.py
@@ -39,7 +39,7 @@
     release_status = "Development Status :: 5 - Production/Stable"
 
 dependencies = [
-    "google-api-core[grpc] >= 2.11.0, <3.0.0",
+    "google-api-core[grpc] >= 2.17.1, <3.0.0",
     # Exclude incompatible versions of `google-auth`
     # See https://github.com/googleapis/google-cloud-python/issues/12364
     "google-auth >= 2.14.1, <3.0.0,!=2.24.0,!=2.25.0",
diff --git a/tests/integration/goldens/logging/testing/constraints-3.9.txt b/tests/integration/goldens/logging/testing/constraints-3.9.txt
index ac3833d41b..d5ce286e09 100755
--- a/tests/integration/goldens/logging/testing/constraints-3.9.txt
+++ b/tests/integration/goldens/logging/testing/constraints-3.9.txt
@@ -5,9 +5,8 @@
 # pinning their versions to their lower bounds.
 # For example, if setup.py has "google-cloud-foo >= 1.14.0, < 2.0.0",
 # then this file should have google-cloud-foo==1.14.0
-google-api-core==2.21.0
-google-auth==2.35.0
-# TODO(https://github.com/googleapis/gapic-generator-python/issues/2453)
-# Add the minimum supported version of grpcio to constraints files
+google-api-core==2.17.1
+google-auth==2.14.1
+grpcio==1.33.2  # from google-api-core
 proto-plus==1.22.3
 protobuf==4.25.8
diff --git a/tests/integration/goldens/logging_internal/setup.py b/tests/integration/goldens/logging_internal/setup.py
index 0b99458443..2f1b079f1b 100755
--- a/tests/integration/goldens/logging_internal/setup.py
+++ b/tests/integration/goldens/logging_internal/setup.py
@@ -39,7 +39,7 @@
     release_status = "Development Status :: 5 - Production/Stable"
 
 dependencies = [
-    "google-api-core[grpc] >= 2.11.0, <3.0.0",
+    "google-api-core[grpc] >= 2.17.1, <3.0.0",
     # Exclude incompatible versions of `google-auth`
     # See https://github.com/googleapis/google-cloud-python/issues/12364
     "google-auth >= 2.14.1, <3.0.0,!=2.24.0,!=2.25.0",
diff --git a/tests/integration/goldens/logging_internal/testing/constraints-3.9.txt b/tests/integration/goldens/logging_internal/testing/constraints-3.9.txt
index ac3833d41b..d5ce286e09 100755
--- a/tests/integration/goldens/logging_internal/testing/constraints-3.9.txt
+++ b/tests/integration/goldens/logging_internal/testing/constraints-3.9.txt
@@ -5,9 +5,8 @@
 # pinning their versions to their lower bounds.
 # For example, if setup.py has "google-cloud-foo >= 1.14.0, < 2.0.0",
 # then this file should have google-cloud-foo==1.14.0
-google-api-core==2.21.0
-google-auth==2.35.0
-# TODO(https://github.com/googleapis/gapic-generator-python/issues/2453)
-# Add the minimum supported version of grpcio to constraints files
+google-api-core==2.17.1
+google-auth==2.14.1
+grpcio==1.33.2  # from google-api-core
 proto-plus==1.22.3
 protobuf==4.25.8
diff --git a/tests/integration/goldens/redis/setup.py b/tests/integration/goldens/redis/setup.py
index 2cf3926c8e..29648855db 100755
--- a/tests/integration/goldens/redis/setup.py
+++ b/tests/integration/goldens/redis/setup.py
@@ -39,7 +39,7 @@
     release_status = "Development Status :: 5 - Production/Stable"
 
 dependencies = [
-    "google-api-core[grpc] >= 2.11.0, <3.0.0",
+    "google-api-core[grpc] >= 2.17.1, <3.0.0",
     # Exclude incompatible versions of `google-auth`
     # See https://github.com/googleapis/google-cloud-python/issues/12364
     "google-auth >= 2.14.1, <3.0.0,!=2.24.0,!=2.25.0",
diff --git a/tests/integration/goldens/redis/testing/constraints-3.9-async-rest.txt b/tests/integration/goldens/redis/testing/constraints-3.9-async-rest.txt
new file mode 100644
index 0000000000..0845245d47
--- /dev/null
+++ b/tests/integration/goldens/redis/testing/constraints-3.9-async-rest.txt
@@ -0,0 +1,12 @@
+# -*- coding: utf-8 -*-
+# This constraints file is used to check that lower bounds
+# are correct in setup.py
+# List all library dependencies and extras in this file,
+# pinning their versions to their lower bounds.
+# For example, if setup.py has "google-cloud-foo >= 1.14.0, < 2.0.0",
+# then this file should have google-cloud-foo==1.14.0
+google-api-core==2.21.0
+google-auth==2.35.0
+grpcio==1.33.2  # from google-api-core
+proto-plus==1.22.3
+protobuf==4.25.8
diff --git a/tests/integration/goldens/redis/testing/constraints-3.9.txt b/tests/integration/goldens/redis/testing/constraints-3.9.txt
index ac3833d41b..d5ce286e09 100755
--- a/tests/integration/goldens/redis/testing/constraints-3.9.txt
+++ b/tests/integration/goldens/redis/testing/constraints-3.9.txt
@@ -5,9 +5,8 @@
 # pinning their versions to their lower bounds.
 # For example, if setup.py has "google-cloud-foo >= 1.14.0, < 2.0.0",
 # then this file should have google-cloud-foo==1.14.0
-google-api-core==2.21.0
-google-auth==2.35.0
-# TODO(https://github.com/googleapis/gapic-generator-python/issues/2453)
-# Add the minimum supported version of grpcio to constraints files
+google-api-core==2.17.1
+google-auth==2.14.1
+grpcio==1.33.2  # from google-api-core
 proto-plus==1.22.3
 protobuf==4.25.8
diff --git a/tests/integration/goldens/redis_selective/setup.py b/tests/integration/goldens/redis_selective/setup.py
index 2cf3926c8e..29648855db 100755
--- a/tests/integration/goldens/redis_selective/setup.py
+++ b/tests/integration/goldens/redis_selective/setup.py
@@ -39,7 +39,7 @@
     release_status = "Development Status :: 5 - Production/Stable"
 
 dependencies = [
-    "google-api-core[grpc] >= 2.11.0, <3.0.0",
+    "google-api-core[grpc] >= 2.17.1, <3.0.0",
     # Exclude incompatible versions of `google-auth`
     # See https://github.com/googleapis/google-cloud-python/issues/12364
     "google-auth >= 2.14.1, <3.0.0,!=2.24.0,!=2.25.0",
diff --git a/tests/integration/goldens/redis_selective/testing/constraints-3.9-async-rest.txt b/tests/integration/goldens/redis_selective/testing/constraints-3.9-async-rest.txt
new file mode 100644
index 0000000000..0845245d47
--- /dev/null
+++ b/tests/integration/goldens/redis_selective/testing/constraints-3.9-async-rest.txt
@@ -0,0 +1,12 @@
+# -*- coding: utf-8 -*-
+# This constraints file is used to check that lower bounds
+# are correct in setup.py
+# List all library dependencies and extras in this file,
+# pinning their versions to their lower bounds.
+# For example, if setup.py has "google-cloud-foo >= 1.14.0, < 2.0.0",
+# then this file should have google-cloud-foo==1.14.0
+google-api-core==2.21.0
+google-auth==2.35.0
+grpcio==1.33.2  # from google-api-core
+proto-plus==1.22.3
+protobuf==4.25.8
diff --git a/tests/integration/goldens/redis_selective/testing/constraints-3.9.txt b/tests/integration/goldens/redis_selective/testing/constraints-3.9.txt
index ac3833d41b..d5ce286e09 100755
--- a/tests/integration/goldens/redis_selective/testing/constraints-3.9.txt
+++ b/tests/integration/goldens/redis_selective/testing/constraints-3.9.txt
@@ -5,9 +5,8 @@
 # pinning their versions to their lower bounds.
 # For example, if setup.py has "google-cloud-foo >= 1.14.0, < 2.0.0",
 # then this file should have google-cloud-foo==1.14.0
-google-api-core==2.21.0
-google-auth==2.35.0
-# TODO(https://github.com/googleapis/gapic-generator-python/issues/2453)
-# Add the minimum supported version of grpcio to constraints files
+google-api-core==2.17.1
+google-auth==2.14.1
+grpcio==1.33.2  # from google-api-core
 proto-plus==1.22.3
 protobuf==4.25.8