diff --git a/.docker/cp2k-code.yml b/.docker/cp2k-code.yml
index d38915f..cc6b0a0 100644
--- a/.docker/cp2k-code.yml
+++ b/.docker/cp2k-code.yml
@@ -6,4 +6,4 @@ filepath_executable: /opt/conda/envs/cp2k/bin/cp2k.psmp
 append_text:
 prepend_text: |
   eval "$(command conda shell.bash hook 2> /dev/null)"
-  conda activate cp2k
+  mamba activate cp2k
diff --git a/Dockerfile b/Dockerfile
index 7e47034..b08ee41 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -19,7 +19,7 @@ RUN set -ex ; \
 
 USER aiida
 
-RUN conda create --yes -c conda-forge -n cp2k cp2k=9.1 && conda clean --all -f -y
+RUN mamba create --yes -c conda-forge -n cp2k cp2k=9.1 && mamba clean --all -f -y
 
 # Install aiida-cp2k plugin.
 COPY --chown="${SYSTEM_UID}:${SYSTEM_GID}" . /home/aiida/aiida-cp2k
diff --git a/conftest.py b/conftest.py
index fd00978..d9455ec 100644
--- a/conftest.py
+++ b/conftest.py
@@ -9,7 +9,7 @@ def cp2k_code(aiida_local_code_factory):
     return aiida_local_code_factory(
         entry_point="cp2k",
         executable="/opt/conda/envs/cp2k/bin/cp2k.psmp",
-        prepend_text='eval "$(command conda shell.bash hook 2> /dev/null)"\nconda activate cp2k\n',
+        prepend_text='eval "$(command conda shell.bash hook 2> /dev/null)"\nmamba activate cp2k\n',
     )