diff --git a/source/includes/authenticated_api/_signatures.md.erb b/source/includes/authenticated_api/_signatures.md.erb
index bf377a9da7e..73340957ff5 100644
--- a/source/includes/authenticated_api/_signatures.md.erb
+++ b/source/includes/authenticated_api/_signatures.md.erb
@@ -28,7 +28,7 @@ was recorded against.
     "first_name": "Foo",
     "join_organisation": true,
     "last_name": "Bar",
-    "phone_number": "123-456",
+    "phone_number": "555-555-5555",
     "postcode": "10010",
     "source": "",
     "token": "abcDEFghi123456789jklMNO",
@@ -141,7 +141,7 @@ The JSON response has a single "signature" object, which may include the followi
     "last_name": "Bar",
     "email": "foo@bar.com",
     "postcode": "10010",
-    "phone_number": "123-456",
+    "phone_number": "555-555-5555",
     "country": "US",
     "email_opt_in_type_external_id": "abcd12345",
     "join_organisation": true
@@ -172,7 +172,7 @@ The JSON response has a single "signature" object, which may include the followi
     "first_name": "Foo",
     "join_organisation": true,
     "last_name": "Bar",
-    "phone_number": "123-456",
+    "phone_number": "555-555-5555",
     "postcode": "10010",
     "source": "",
     "token": "abcDEFghi123456789jklMNO",
@@ -291,7 +291,7 @@ Permanently deletes the signature with the specified ID. Note that this will dec
       "first_name": "Foo",
       "join_organisation": true,
       "last_name": "Bar",
-      "phone_number": "123-456",
+      "phone_number": "555-555-5555",
       "postcode": "10010",
       "source": "",
       "token": "abcDEFghi123456789jklMNO",