diff --git a/param_templates/MOM_input.yaml b/param_templates/MOM_input.yaml
index 4cc2ca80..8663c437 100644
--- a/param_templates/MOM_input.yaml
+++ b/param_templates/MOM_input.yaml
@@ -3709,6 +3709,15 @@ Global:
             checksums will not match and cause crash.
         datatype: logical
         value: $TEST
+    RESTARTFILE_APPENDIX_PREFIX:
+        description: |
+            "default = ''
+            The prefix for the restart file appendix (i.e., ensemble id for ensemble
+            runs). If this prefix is found in the restart file name, the appendix is added
+            right after the first occurrence of the prefix. If not found, the appendix is
+            added to the end of the file name. This parameter is ignored for non-ensemble runs."
+        datatype: string
+        value: ".mom6"
 KPP:
     N_SMOOTH:
         description: |
diff --git a/param_templates/json/MOM_input.json b/param_templates/json/MOM_input.json
index 2f4620ac..afa8ea32 100644
--- a/param_templates/json/MOM_input.json
+++ b/param_templates/json/MOM_input.json
@@ -3003,6 +3003,11 @@
          "description": "\"[Boolean] default = True\nIf true, require the restart checksums to match and error out otherwise. Users\nmay want to avoid this comparison if for example the restarts are made from a\nrun with a different mask_table than the current run, in which case the\nchecksums will not match and cause crash.\n",
          "datatype": "logical",
          "value": "$TEST"
+      },
+      "RESTARTFILE_APPENDIX_PREFIX": {
+         "description": "\"default = ''\nThe prefix for the restart file appendix (i.e., ensemble id for ensemble\nruns). If this prefix is found in the restart file name, the appendix is added\nright after the first occurrence of the prefix. If not found, the appendix is\nadded to the end of the file name. This parameter is ignored for non-ensemble runs.\"\n",
+         "datatype": "string",
+         "value": ".mom6"
       }
    },
    "KPP": {