diff --git a/news/13378.bugfix.rst b/news/13378.bugfix.rst
new file mode 100644
index 00000000000..123dae3f942
--- /dev/null
+++ b/news/13378.bugfix.rst
@@ -0,0 +1,2 @@
+Fix missing ``network`` test markings, making the suite pass in offline
+environments again.
diff --git a/tests/functional/test_config_settings.py b/tests/functional/test_config_settings.py
index 4e0b12ca185..7675e841274 100644
--- a/tests/functional/test_config_settings.py
+++ b/tests/functional/test_config_settings.py
@@ -4,6 +4,8 @@
 from typing import List, Optional, Tuple
 from zipfile import ZipFile
 
+import pytest
+
 from pip._internal.utils.urls import path_to_url
 
 from tests.lib import PipTestEnvironment, create_basic_sdist_for_package
@@ -179,6 +181,7 @@ def test_backend_sees_config_via_constraint(script: PipTestEnvironment) -> None:
             assert json.loads(output) == {"FOO": "Hello"}
 
 
+@pytest.mark.network
 def test_backend_sees_config_via_sdist(script: PipTestEnvironment) -> None:
     name, version, project_dir = make_project(script.scratch_path)
     dists_dir = script.scratch_path / "dists"
diff --git a/tests/functional/test_install.py b/tests/functional/test_install.py
index 1dc46cf8621..472c7de5987 100644
--- a/tests/functional/test_install.py
+++ b/tests/functional/test_install.py
@@ -1917,6 +1917,7 @@ def test_double_install(script: PipTestEnvironment) -> None:
     assert msg not in result.stderr
 
 
+@pytest.mark.network
 def test_double_install_fail(
     script: PipTestEnvironment, resolver_variant: ResolverVariant
 ) -> None:
@@ -2677,6 +2678,7 @@ def test_install_pip_prints_req_chain_pypi(script: PipTestEnvironment) -> None:
 
 
 @pytest.mark.parametrize("common_prefix", ["", "linktest-1.0/"])
+@pytest.mark.network
 def test_install_sdist_links(script: PipTestEnvironment, common_prefix: str) -> None:
     """
     Test installing an sdist with hard and symbolic links.
diff --git a/tests/functional/test_install_config.py b/tests/functional/test_install_config.py
index b8fa56bffc9..7ca9eb2469e 100644
--- a/tests/functional/test_install_config.py
+++ b/tests/functional/test_install_config.py
@@ -417,6 +417,7 @@ def flags(
     return flags
 
 
+@pytest.mark.network
 def test_prompt_for_keyring_if_needed(
     data: TestData,
     cert_factory: CertFactory,
diff --git a/tests/functional/test_lock.py b/tests/functional/test_lock.py
index b99850526e1..727bd72c8a0 100644
--- a/tests/functional/test_lock.py
+++ b/tests/functional/test_lock.py
@@ -1,6 +1,8 @@
 import textwrap
 from pathlib import Path
 
+import pytest
+
 from pip._internal.utils.compat import tomllib
 from pip._internal.utils.urls import path_to_url
 
@@ -181,6 +183,7 @@ def test_lock_local_editable_with_dep(
     ]
 
 
+@pytest.mark.network
 def test_lock_vcs(script: PipTestEnvironment, shared_data: TestData) -> None:
     result = script.pip(
         "lock",
@@ -205,6 +208,7 @@ def test_lock_vcs(script: PipTestEnvironment, shared_data: TestData) -> None:
     ]
 
 
+@pytest.mark.network
 def test_lock_archive(script: PipTestEnvironment, shared_data: TestData) -> None:
     result = script.pip(
         "lock",