diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5edd85dcf..db063efce 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,7 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 - Added `_common.mapping:FlatObjectProperty` ([#661](https://github.com/opensearch-project/opensearch-api-specification/pull/661)) 
 - Added `HEAD /{index}/_doc/{id}` returning `404` ([#670](https://github.com/opensearch-project/opensearch-api-specification/pull/670))
 - Added `_common.mapping:IcuCollationKeywordProperty` ([#666](https://github.com/opensearch-project/opensearch-api-specification/pull/666))
+- Added `GET` and `HEAD /{index}/_source/{id}` returning `404` ([#](https://github.com/opensearch-project/opensearch-api-specification/pull/))
 
 ### Removed
 - Removed unsupported `_common.mapping:SourceField`'s `mode` field and associated `_common.mapping:SourceFieldMode` enum ([#652](https://github.com/opensearch-project/opensearch-api-specification/pull/652))
diff --git a/spec/namespaces/_core.yaml b/spec/namespaces/_core.yaml
index 542d55bf2..a6550f87a 100644
--- a/spec/namespaces/_core.yaml
+++ b/spec/namespaces/_core.yaml
@@ -2047,6 +2047,8 @@ paths:
       responses:
         '200':
           $ref: '#/components/responses/get_source@200'
+        '404':
+          $ref: '#/components/responses/get_source@404'
     head:
       operationId: exists_source.0
       x-operation-group: exists_source
@@ -2069,6 +2071,8 @@ paths:
       responses:
         '200':
           $ref: '#/components/responses/exists_source@200'
+        '404':
+          $ref: '#/components/responses/exists_source@404'
   /{index}/_termvectors:
     get:
       operationId: termvectors.0
@@ -2913,6 +2917,9 @@ components:
     exists_source@200:
       content:
         application/json: {}
+    exists_source@404:
+      content:
+        application/json: {}
     explain@200:
       content:
         application/json:
@@ -3019,6 +3026,11 @@ components:
         application/json:
           schema:
             type: object
+    get_source@404:
+      content:
+        application/json:
+          schema:
+            $ref: '../schemas/query._common.yaml#/components/schemas/ErrorResponse'
     index@200:
       content:
         application/json:
diff --git a/tests/default/indices/source.yaml b/tests/default/indices/source.yaml
new file mode 100644
index 000000000..4d7c234c2
--- /dev/null
+++ b/tests/default/indices/source.yaml
@@ -0,0 +1,52 @@
+$schema: ../../../json_schemas/test_story.schema.yaml
+
+description: Test retrieving a document source.
+epilogues:
+  - path: /movies
+    method: DELETE
+    status: [200, 404]
+prologues:
+  - path: /movies/_doc/1
+    method: POST
+    parameters:
+      refresh: true
+    request:
+      payload:
+        title: Beauty and the Beast
+        year: 1991
+chapters:
+  - synopsis: Retrieve the document source.
+    path: /{index}/_source/{id}
+    method: GET
+    parameters:
+      index: movies
+      id: '1'
+    response:
+      status: 200
+      payload:
+        title: Beauty and the Beast
+        year: 1991
+  - synopsis: Retrieve a non-existent document source.
+    path: /{index}/_source/{id}
+    method: GET
+    parameters:
+      index: movies
+      id: '2'
+    response:
+      status: 404
+  - synopsis: Check whether the document exists.
+    path: /{index}/_source/{id}
+    method: HEAD
+    parameters:
+      index: movies
+      id: '1'
+    response:
+      status: 200
+  - synopsis: Check whether the document exists.
+    path: /{index}/_source/{id}
+    method: HEAD
+    parameters:
+      index: movies
+      id: '2'
+    response:
+      status: 404