diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 4a31a13af7d..0c7543a6906 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -47,7 +47,7 @@ jobs:
       matrix:
         os: ["ubuntu-latest", "macos-latest", "windows-latest"]
         # Bookend python versions
-        python-version: ["3.10", "3.12"]
+        python-version: ["3.10", "3.12", "3.13"]
         env: [""]
         include:
           # Minimum python version:
diff --git a/ci/requirements/environment-3.13.yml b/ci/requirements/environment-3.13.yml
index dbb446f4454..f43a5f70735 100644
--- a/ci/requirements/environment-3.13.yml
+++ b/ci/requirements/environment-3.13.yml
@@ -34,7 +34,7 @@ dependencies:
   - pip
   - pooch
   - pre-commit
-  - pydap
+  # - pydap
   - pytest
   - pytest-cov
   - pytest-env
diff --git a/ci/requirements/environment-windows-3.13.yml b/ci/requirements/environment-windows-3.13.yml
index 448e3f70c0c..b699dc1b482 100644
--- a/ci/requirements/environment-windows-3.13.yml
+++ b/ci/requirements/environment-windows-3.13.yml
@@ -29,7 +29,7 @@ dependencies:
   # - pint>=0.22
   - pip
   - pre-commit
-  - pydap
+  # - pydap
   - pytest
   - pytest-cov
   - pytest-env
diff --git a/doc/whats-new.rst b/doc/whats-new.rst
index 9ca3474d256..2d4a71f443d 100644
--- a/doc/whats-new.rst
+++ b/doc/whats-new.rst
@@ -26,6 +26,8 @@ Benoit Bovy, Deepak Cherian, Dimitri Papadopoulos Orfanos, Holly Mandel, James B
 
 New Features
 ~~~~~~~~~~~~
+- support python 3.13 (no free-threading) (:issue:`9664`, :pull:`9681`)
+  By `Justus Magin <https://github.com/keewis>`_.
 - Added :py:meth:`DataTree.persist` method (:issue:`9675`, :pull:`9682`).
   By `Sam Levang <https://github.com/slevang>`_.
 - Added ``write_inherited_coords`` option to :py:meth:`DataTree.to_netcdf`
diff --git a/pyproject.toml b/pyproject.toml
index dab280f0eba..0d68b4545cb 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -12,6 +12,7 @@ classifiers = [
   "Programming Language :: Python :: 3.10",
   "Programming Language :: Python :: 3.11",
   "Programming Language :: Python :: 3.12",
+  "Programming Language :: Python :: 3.13",
   "Topic :: Scientific/Engineering",
 ]
 description = "N-D labeled arrays and datasets in Python"