diff --git a/steps/bucket_push_file.cwl b/steps/bucket_push_file.cwl
index 09035b7f663a6aea77c08eef8077c51d531c1956..223ed43b95ed66dc77a359d4aa62eba7f9878e0c 100644
--- a/steps/bucket_push_file.cwl
+++ b/steps/bucket_push_file.cwl
@@ -6,7 +6,7 @@ baseCommand: bucket_push_file.py
 label: "Push a folder to an EBRAINS Collaboratory Bucket"
 hints:
   DockerRequirement:
-    dockerPull: docker-registry.ebrains.eu/sc3/bucket_push_file:latest
+    dockerPull: docker-registry.ebrains.eu/sc3/bucket_push_file@sha256:b309e1fcff9bd43bde370c0c346a458db206e03233522ea3ec4dbc0b45050431
 
 inputs:
   bucket_id:
diff --git a/steps/plot_results.cwl b/steps/plot_results.cwl
index 701ce51d17b09788f0f64f104e9d87b1989becf0..aab10d1b303c6718820d8dacbe79f5e4ead3a9e5 100644
--- a/steps/plot_results.cwl
+++ b/steps/plot_results.cwl
@@ -6,7 +6,7 @@ baseCommand: plot_results.py
 label: "HBP Showcase 3: Plot results"
 hints:
   DockerRequirement:
-    dockerPull: docker-registry.ebrains.eu/sc3/plot_results:latest
+    dockerPull: docker-registry.ebrains.eu/sc3/plot_results@sha256:148c230a9d62cc217e24f0c39c1269829e766e9be926fbd1584914eb3ffd5eee
 
 inputs:
   results_folder:
diff --git a/steps/run_simulation.cwl b/steps/run_simulation.cwl
index c8d04b28ba0d70517f512eecb4d445d6b0a8059e..8297de2b6e23fced2a5ebcebccb92fc7b3e9e8ce 100644
--- a/steps/run_simulation.cwl
+++ b/steps/run_simulation.cwl
@@ -6,7 +6,7 @@ baseCommand: run_simulation.py
 label: "HBP Showcase 3: Run simulation"
 hints:
   DockerRequirement:
-    dockerPull: docker-registry.ebrains.eu/sc3/run_simulation:latest
+    dockerPull: docker-registry.ebrains.eu/sc3/run_simulation@sha256:915468bc91013e3d742d97e9bbe00373a1b243a1f70c2560fe29aac94d30fa4d
 
 inputs:
   folder_root: