diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 9e7a820..537437a 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -24,6 +24,8 @@ jobs:
           activate-environment: cf_tools_test
           auto-update-conda: false
           python-version: ${{ matrix.python-version }}
+          miniforge-variant: Mambaforge
+          use-mamba: true
 
       - name: Set up conda environment
         shell: bash -l {0}
@@ -54,6 +56,8 @@ jobs:
           environment-file: ci/upsteam_dev_env.yml
           activate-environment: cf_tools_test_dev
           auto-update-conda: false
+          miniforge-variant: Mambaforge
+          use-mamba: true
 
       - name: Set up conda environment
         shell: bash -l {0}