diff --git a/.github/workflows/commit-ci.yml b/.github/workflows/commit-ci.yml
index b8d81e51..0d023538 100644
--- a/.github/workflows/commit-ci.yml
+++ b/.github/workflows/commit-ci.yml
@@ -27,7 +27,7 @@ jobs:
 
     - uses: mamba-org/setup-micromamba@v1
       with:
-        micromamba-version: latest
+        micromamba-version: "1.5.10"
         environment-name: ${{ github.event.repository.name }}-ubuntu-latest-312-${{ hashFiles('requirements/dev.txt') }}
         environment-file: requirements/base.txt
         create-args: >-
diff --git a/.github/workflows/pr-ci.yml b/.github/workflows/pr-ci.yml
index c989b30c..681dddda 100644
--- a/.github/workflows/pr-ci.yml
+++ b/.github/workflows/pr-ci.yml
@@ -45,7 +45,7 @@ jobs:
 
     - uses: mamba-org/setup-micromamba@v1
       with:
-        micromamba-version: latest
+        micromamba-version: "1.5.10"
         environment-name: ${{ github.event.repository.name }}-${{ matrix.os }}-3${{ matrix.py3version }}-${{ hashFiles('requirements/dev.txt') }}
         environment-file: requirements/base.txt
         create-args: >-
@@ -108,7 +108,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: mamba-org/setup-micromamba@v1
         with:
-          micromamba-version: latest
+          micromamba-version: "1.5.10"
           environment-file: .github/workflows/pr-ci-pipbuild-environment.yml
           post-cleanup: all
           cache-environment: true
@@ -127,4 +127,4 @@ jobs:
       TEST_PYPI_API_TOKEN: ${{ secrets.TEST_PYPI_API_TOKEN }}
     with:
       package_name: calliope
-      version: ${{needs.pre-release-version.outputs.version}}
\ No newline at end of file
+      version: ${{needs.pre-release-version.outputs.version}}