diff --git a/.circleci/config.yml b/.circleci/config.yml
index 7b3376afc7..c0b76b26c4 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -209,7 +209,7 @@ jobs:
             # Install prerequisites
             mkdir /logs
             # Create and activate conda environment
-            mamba create -y --name esmvaltool 'python=3.11'
+            mamba create -y --name esmvaltool 'python=3.12'
             set +x; conda activate esmvaltool; set -x
             # Install
             mamba install -y esmvalcore
diff --git a/.github/workflows/install-from-conda.yml b/.github/workflows/install-from-conda.yml
index 4f860365f9..85ab40e3f8 100644
--- a/.github/workflows/install-from-conda.yml
+++ b/.github/workflows/install-from-conda.yml
@@ -40,7 +40,7 @@ jobs:
     if: github.repository == 'ESMValGroup/ESMValCore'  # avoid GAs in forks
     strategy:
       matrix:
-        python-version: ["3.11", "3.12", "3.13"]
+        python-version: ["3.12", "3.13"]
       # fail-fast set to False allows all other tests
       # in the workflow to run regardless of any fail
       fail-fast: false
@@ -76,7 +76,7 @@ jobs:
     if: github.repository == 'ESMValGroup/ESMValCore'  # avoid GAs in forks
     strategy:
       matrix:
-        python-version: ["3.11", "3.12", "3.13"]
+        python-version: ["3.12", "3.13"]
         architecture: ["x64"]  # need to force Intel, arm64 builds have issues
       fail-fast: false
     name: OSX Python ${{ matrix.python-version }}
diff --git a/.github/workflows/install-from-condalock-file.yml b/.github/workflows/install-from-condalock-file.yml
index 98df15c49e..2ecda585f3 100644
--- a/.github/workflows/install-from-condalock-file.yml
+++ b/.github/workflows/install-from-condalock-file.yml
@@ -30,7 +30,7 @@ jobs:
     if: github.repository == 'ESMValGroup/ESMValCore'  # avoid GAs in forks
     strategy:
       matrix:
-        python-version: ["3.11", "3.12", "3.13"]
+        python-version: ["3.12", "3.13"]
       fail-fast: false
     name: Linux Python ${{ matrix.python-version }}
     steps:
diff --git a/.github/workflows/install-from-pypi.yml b/.github/workflows/install-from-pypi.yml
index 378fa8ecb5..9649423ee1 100644
--- a/.github/workflows/install-from-pypi.yml
+++ b/.github/workflows/install-from-pypi.yml
@@ -40,7 +40,7 @@ jobs:
     if: github.repository == 'ESMValGroup/ESMValCore'  # avoid GAs in forks
     strategy:
       matrix:
-        python-version: ["3.11", "3.12", "3.13"]
+        python-version: ["3.12", "3.13"]
       # fail-fast set to False allows all other tests
       # in the workflow to run regardless of any fail
       fail-fast: false
@@ -79,7 +79,7 @@ jobs:
     if: github.repository == 'ESMValGroup/ESMValCore'  # avoid GAs in forks
     strategy:
       matrix:
-        python-version: ["3.11", "3.12", "3.13"]
+        python-version: ["3.12", "3.13"]
         architecture: ["x64"]  # need to force Intel, arm64 builds have issues
       fail-fast: false
     name: OSX Python ${{ matrix.python-version }}
diff --git a/.github/workflows/install-from-source.yml b/.github/workflows/install-from-source.yml
index 028068acc9..bf6133a40a 100644
--- a/.github/workflows/install-from-source.yml
+++ b/.github/workflows/install-from-source.yml
@@ -38,7 +38,7 @@ jobs:
     if: github.repository == 'ESMValGroup/ESMValCore'  # avoid GAs in forks
     strategy:
       matrix:
-        python-version: ["3.11", "3.12", "3.13"]
+        python-version: ["3.12", "3.13"]
       fail-fast: false
     name: Linux Python ${{ matrix.python-version }}
     steps:
@@ -76,7 +76,7 @@ jobs:
     if: github.repository == 'ESMValGroup/ESMValCore'  # avoid GAs in forks
     strategy:
       matrix:
-        python-version: ["3.11", "3.12", "3.13"]
+        python-version: ["3.12", "3.13"]
         architecture: ["x64"]  # need to force Intel, arm64 builds have issues
       fail-fast: false
     name: OSX Python ${{ matrix.python-version }}
diff --git a/.github/workflows/run-tests-monitor.yml b/.github/workflows/run-tests-monitor.yml
index 281a8f58ae..a71967b311 100644
--- a/.github/workflows/run-tests-monitor.yml
+++ b/.github/workflows/run-tests-monitor.yml
@@ -23,7 +23,7 @@ jobs:
     if: github.repository == 'ESMValGroup/ESMValCore'  # avoid GAs in forks
     strategy:
       matrix:
-        python-version: ["3.11", "3.12", "3.13"]
+        python-version: ["3.12", "3.13"]
       fail-fast: false
     name: Linux Python ${{ matrix.python-version }}
     steps:
@@ -56,7 +56,7 @@ jobs:
     if: github.repository == 'ESMValGroup/ESMValCore'  # avoid GAs in forks
     strategy:
       matrix:
-        python-version: ["3.11", "3.12", "3.13"]
+        python-version: ["3.12", "3.13"]
         architecture: ["x64"]  # need to force Intel, arm64 builds have issues
       fail-fast: false
     name: OSX Python ${{ matrix.python-version }}
diff --git a/.github/workflows/run-tests.yml b/.github/workflows/run-tests.yml
index 625e3b9c95..39c1e0ac50 100644
--- a/.github/workflows/run-tests.yml
+++ b/.github/workflows/run-tests.yml
@@ -40,7 +40,7 @@ jobs:
     if: github.repository == 'ESMValGroup/ESMValCore'  # avoid GAs in forks
     strategy:
       matrix:
-        python-version: ["3.11", "3.12", "3.13"]
+        python-version: ["3.12", "3.13"]
       fail-fast: false
     name: Linux Python ${{ matrix.python-version }}
     steps:
@@ -77,7 +77,7 @@ jobs:
     if: github.repository == 'ESMValGroup/ESMValCore'  # avoid GAs in forks
     strategy:
       matrix:
-        python-version: ["3.11", "3.12", "3.13"]
+        python-version: ["3.12", "3.13"]
         architecture: ["x64"]  # need to force Intel, arm64 builds have issues
       fail-fast: false
     name: OSX Python ${{ matrix.python-version }}
diff --git a/environment.yml b/environment.yml
index 78102cc380..ab1acac982 100644
--- a/environment.yml
+++ b/environment.yml
@@ -40,7 +40,7 @@ dependencies:
   - psutil
   - py-cordex
   - pybtex
-  - python >=3.11
+  - python >=3.12
   - python-stratify >=0.3
   - pyyaml
   - requests
diff --git a/esmvalcore/preprocessor/__init__.py b/esmvalcore/preprocessor/__init__.py
index de4337f948..8b48058d64 100644
--- a/esmvalcore/preprocessor/__init__.py
+++ b/esmvalcore/preprocessor/__init__.py
@@ -6,7 +6,7 @@
 import inspect
 import logging
 from pprint import pformat
-from typing import TYPE_CHECKING, Any, TypeAlias
+from typing import TYPE_CHECKING, Any
 
 from iris.cube import Cube, CubeList
 
@@ -672,7 +672,7 @@ def group(self, keys: list) -> str:
         return "_".join(identifier)
 
 
-PreprocessorItem: TypeAlias = PreprocessorFile | Cube | DataElement
+type PreprocessorItem = PreprocessorFile | Cube | DataElement
 
 
 def _apply_multimodel(
diff --git a/pyproject.toml b/pyproject.toml
index 22721ed465..302cbcee31 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -18,7 +18,6 @@ classifiers = [
     "Natural Language :: English",
     "Operating System :: POSIX :: Linux",
     "Programming Language :: Python :: 3",
-    "Programming Language :: Python :: 3.11",
     "Programming Language :: Python :: 3.12",
     "Programming Language :: Python :: 3.13",
     "Topic :: Scientific/Engineering",
@@ -75,7 +74,7 @@ dependencies = [
 description = "A community tool for pre-processing data from Earth system models in CMIP and running analysis scripts"
 license = {text = "Apache License, Version 2.0"}
 name = "ESMValCore"
-requires-python = ">=3.11"
+requires-python = ">=3.12"
 
 [project.optional-dependencies]
 test = [