diff --git a/changelogs/fragments/deprecated_string_conversion_action.yml b/changelogs/fragments/deprecated_string_conversion_action.yml
new file mode 100644
index 00000000000..a80809223aa
--- /dev/null
+++ b/changelogs/fragments/deprecated_string_conversion_action.yml
@@ -0,0 +1,2 @@
+deprecated_features:
+  - "``STRING_CONVERSION_ACTION`` config option is deprecated as it is no longer used in the Ansible Core code base."
diff --git a/lib/ansible/config/base.yml b/lib/ansible/config/base.yml
index ae846330fd5..3b795553eb9 100644
--- a/lib/ansible/config/base.yml
+++ b/lib/ansible/config/base.yml
@@ -2073,6 +2073,10 @@ STRING_CONVERSION_ACTION:
     - section: defaults
       key: string_conversion_action
   type: string
+  deprecated:
+    why: This option is no longer used in the Ansible Core code base.
+    version: "2.19"
+    alternatives: There is no alternative at the moment. A different mechanism would have to be implemented in the current code base.
 VALIDATE_ACTION_GROUP_METADATA:
   version_added: '2.12'
   description: