diff --git a/docs/release-notes/version-3.1.md b/docs/release-notes/version-3.1.md
index fb02055f2..ee7df6d0c 100644
--- a/docs/release-notes/version-3.1.md
+++ b/docs/release-notes/version-3.1.md
@@ -5,6 +5,7 @@
 ### Bug Fixes
 
 * [#5869](https://github.com/netbox-community/netbox/issues/5869) - Fix permissions evaluation under available prefix/IP REST API endpoints
+* [#7519](https://github.com/netbox-community/netbox/issues/7519) - Return a 409 status for unfulfillable available prefix/IP requests
 * [#7990](https://github.com/netbox-community/netbox/issues/7990) - Fix `title` display on contact detail view
 * [#7996](https://github.com/netbox-community/netbox/issues/7996) - Show WWN field in interface creation form
 * [#8001](https://github.com/netbox-community/netbox/issues/8001) - Correct verbose name for wireless LAN group model
diff --git a/netbox/ipam/api/views.py b/netbox/ipam/api/views.py
index f3937c7d6..0d098db4b 100644
--- a/netbox/ipam/api/views.py
+++ b/netbox/ipam/api/views.py
@@ -208,7 +208,7 @@ class AvailablePrefixesView(ObjectValidationMixin, APIView):
                     {
                         "detail": "Insufficient space is available to accommodate the requested prefix size(s)"
                     },
-                    status=status.HTTP_204_NO_CONTENT
+                    status=status.HTTP_409_CONFLICT
                 )
 
             # Remove the allocated prefix from the list of available prefixes
@@ -288,7 +288,7 @@ class AvailableIPAddressesView(ObjectValidationMixin, APIView):
                     "detail": f"An insufficient number of IP addresses are available within {parent} "
                               f"({len(requested_ips)} requested, {len(available_ips)} available)"
                 },
-                status=status.HTTP_204_NO_CONTENT
+                status=status.HTTP_409_CONFLICT
             )
 
         # Assign addresses from the list of available IPs and copy VRF assignment from the parent