diff --git a/.github/workflows/tests_eessi_module.yml b/.github/workflows/tests_eessi_module.yml
index e27494ba..d645e63d 100644
--- a/.github/workflows/tests_eessi_module.yml
+++ b/.github/workflows/tests_eessi_module.yml
@@ -315,3 +315,40 @@ jobs:
           module load "EESSI/${{matrix.EESSI_VERSION}}"
           GREP_PATTERN="Lmod is automatically replacing \"EESSI/${{matrix.EESSI_VERSION}}\" with \"${LOCAL_STACK_NAME}/${LOCAL_STACK_VERSION}\"."
           module load "${LOCAL_STACK_NAME}/${LOCAL_STACK_VERSION}" |& grep "${GREP_PATTERN}"
+
+  check_PS1_update_eessi_module:
+    runs-on: ubuntu-24.04
+    strategy:
+      fail-fast: false
+      matrix:
+        EESSI_VERSION:
+          - '2023.06'
+          - '2025.06'
+
+    steps:
+      - name: Check out software-layer repository
+        uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
+
+      - name: Mount EESSI CernVM-FS repository
+        uses: cvmfs-contrib/github-action-cvmfs@55899ca74cf78ab874bdf47f5a804e47c198743c # v4.0
+        with:
+          cvmfs_config_package: https://github.com/EESSI/filesystem-layer/releases/download/latest/cvmfs-config-eessi_latest_all.deb
+          cvmfs_http_proxy: DIRECT
+          cvmfs_repositories: software.eessi.io
+
+      - name: Make sure we can use EESSI_UPDATE_PS1 to update PS1 in the EESSI module
+        run: |
+          # Initialise Lmod
+          . /cvmfs/software.eessi.io/versions/${{matrix.EESSI_VERSION}}/compat/linux/$(uname -m)/usr/share/Lmod/init/bash
+
+          export MODULEPATH=init/modules
+          # Set the relevant environment variable, load the EESSI module, and grep for what we expect in PS1
+          export EESSI_MODULE_UPDATE_PS1=1
+          # Need to set PS1 manually as we are in a non-interactive shell
+          export PS1="mytest $"
+          echo $PS1
+          module load "EESSI/${{matrix.EESSI_VERSION}}"
+          GREP_PATTERN="{EESSI/${{matrix.EESSI_VERSION}}} "
+          # Pipe the PS1 variable into grep to check for the pattern
+          echo "$PS1"
+          echo "$PS1" | grep "$GREP_PATTERN"
diff --git a/init/modules/EESSI/2023.06.lua b/init/modules/EESSI/2023.06.lua
index 5898bfb8..3ae13bbd 100644
--- a/init/modules/EESSI/2023.06.lua
+++ b/init/modules/EESSI/2023.06.lua
@@ -214,13 +214,26 @@ if family_name then
     family(family_name)
 end
 
+-- change the PS1 if it exists to indicate you have EESSI loaded
+-- (doesn't help with a csh or fish prompt, but we just live with that)
+local quiet_load = false
+if os.getenv("EESSI_MODULE_UPDATE_PS1") then
+    local prompt = os.getenv("PS1")
+    if prompt then
+        quiet_load = true
+        pushenv("PS1", "{EESSI/" .. eessi_version .. "} " .. prompt)
+    end
+end
+
 -- allow sites to make the EESSI module sticky by defining EESSI_MODULE_STICKY (to any value)
-load_message = "Module for EESSI/" .. eessi_version .. " loaded successfully"
+local load_message = "Module for EESSI/" .. eessi_version .. " loaded successfully"
 if os.getenv("EESSI_MODULE_STICKY") then
     add_property("lmod","sticky")
     load_message = load_message .. " (requires '--force' option to unload or purge)"
 end
 
 if mode() == "load" then
-    LmodMessage(load_message)
+    if not quiet_load then
+        LmodMessage(load_message)
+    end
 end