diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index ddbc8a17a9..3a58a92c1e 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -43,6 +43,22 @@ jobs:
         nox-session: ['']
         include:
           - experimental: false
+          # integration
+          # 3.8 and 3.9 have a known issue with large SSL requests that we work around:
+          # https://github.com/urllib3/urllib3/pull/3181#issuecomment-1794830698
+          - python-version: "3.8"
+            os: ubuntu-latest
+            experimental: false
+            nox-session: test_integration
+          - python-version: "3.9"
+            os: ubuntu-latest
+            experimental: false
+            nox-session: test_integration
+          - python-version: "3.12"
+            os: ubuntu-latest
+            experimental: false
+            nox-session: test_integration
+          # pypy
           - python-version: "pypy-3.8"
             os: ubuntu-latest
             experimental: false
@@ -56,6 +72,7 @@ jobs:
             experimental: false
             nox-session: test-pypy
           - python-version: "3.x"
+          # brotli
             os: ubuntu-latest
             experimental: false
             nox-session: test_brotlipy
diff --git a/changelog/3181.feature.rst b/changelog/3181.feature.rst
new file mode 100644
index 0000000000..82d6af24ba
--- /dev/null
+++ b/changelog/3181.feature.rst
@@ -0,0 +1,4 @@
+Note to redistributors: the urllib3 test suite has been separated in
+two. To run integration tests, you now need to run the tests a second
+time with the `--integration` pytest flag, as in this example: `nox
+-rs test-3.12 -- --integration`.
diff --git a/noxfile.py b/noxfile.py
index c0b0b9f0e6..907d82cdd4 100644
--- a/noxfile.py
+++ b/noxfile.py
@@ -11,6 +11,7 @@ def tests_impl(
     session: nox.Session,
     extras: str = "socks,brotli,zstd",
     byte_string_comparisons: bool = True,
+    integration: bool = False,
 ) -> None:
     # Install deps and the package itself.
     session.install("-r", "dev-requirements.txt")
@@ -44,6 +45,7 @@ def tests_impl(
         *("--memray", "--hide-memray-summary") if memray_supported else (),
         "-v",
         "-ra",
+        *(("--integration",) if integration else ()),
         f"--color={'yes' if 'GITHUB_ACTIONS' in os.environ else 'auto'}",
         "--tb=native",
         "--durations=10",
@@ -59,7 +61,13 @@ def test(session: nox.Session) -> None:
     tests_impl(session)
 
 
-@nox.session(python=["3"])
+@nox.session(python="3")
+def test_integration(session: nox.Session) -> None:
+    """Run integration tests"""
+    tests_impl(session, integration=True)
+
+
+@nox.session(python="3")
 def test_brotlipy(session: nox.Session) -> None:
     """Check that if 'brotlipy' is installed instead of 'brotli' or
     'brotlicffi' that we still don't blow up.
diff --git a/pyproject.toml b/pyproject.toml
index bb11c6d0cb..6b850412a1 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -77,6 +77,7 @@ python_classes = ["Test", "*TestCase"]
 markers = [
     "limit_memory: Limit memory with memray",
     "requires_network: This test needs access to the Internet",
+    "integration: Slow integrations tests not run by default",
 ]
 log_level = "DEBUG"
 filterwarnings = [
diff --git a/test/conftest.py b/test/conftest.py
index 9aafdacfac..f464f704c3 100644
--- a/test/conftest.py
+++ b/test/conftest.py
@@ -20,6 +20,32 @@
 from .tz_stub import stub_timezone_ctx
 
 
+def pytest_addoption(parser: pytest.Parser) -> None:
+    parser.addoption(
+        "--integration",
+        action="store_true",
+        default=False,
+        help="run integration tests only",
+    )
+
+
+def pytest_collection_modifyitems(
+    config: pytest.Config, items: list[pytest.Item]
+) -> None:
+    integration_mode = bool(config.getoption("--integration"))
+    skip_integration = pytest.mark.skip(
+        reason="skipping, need --integration option to run"
+    )
+    skip_normal = pytest.mark.skip(
+        reason="skipping non integration tests in --integration mode"
+    )
+    for item in items:
+        if "integration" in item.keywords and not integration_mode:
+            item.add_marker(skip_integration)
+        elif integration_mode and "integration" not in item.keywords:
+            item.add_marker(skip_normal)
+
+
 class ServerConfig(typing.NamedTuple):
     scheme: str
     host: str
diff --git a/test/with_dummyserver/test_socketlevel.py b/test/with_dummyserver/test_socketlevel.py
index 5935888330..c0701fe00a 100644
--- a/test/with_dummyserver/test_socketlevel.py
+++ b/test/with_dummyserver/test_socketlevel.py
@@ -11,7 +11,6 @@
 import shutil
 import socket
 import ssl
-import sys
 import tempfile
 import time
 import typing
@@ -1584,10 +1583,7 @@ def socket_handler(listener: socket.socket) -> None:
                 pool.request("GET", "/", retries=False, timeout=LONG_TIMEOUT)
         assert server_closed.wait(LONG_TIMEOUT), "The socket was not terminated"
 
-    @pytest.mark.skipif(
-        os.environ.get("CI") == "true" and sys.implementation.name == "pypy",
-        reason="too slow to run in CI",
-    )
+    @pytest.mark.integration
     @pytest.mark.parametrize(
         "preload_content,read_amt", [(True, None), (False, None), (False, 2**31)]
     )