diff --git a/.changeset/large-pens-cough.md b/.changeset/large-pens-cough.md
new file mode 100644
index 0000000000..631a20aee2
--- /dev/null
+++ b/.changeset/large-pens-cough.md
@@ -0,0 +1,6 @@
+---
+'@backstage/frontend-plugin-api': patch
+'@backstage/frontend-app-api': patch
+---
+
+Accepts sub route refs on the new `createPlugin` routes map.
diff --git a/packages/frontend-app-api/src/routing/collectRouteIds.ts b/packages/frontend-app-api/src/routing/collectRouteIds.ts
index 1d6aa14e5d..2fbb8b6791 100644
--- a/packages/frontend-app-api/src/routing/collectRouteIds.ts
+++ b/packages/frontend-app-api/src/routing/collectRouteIds.ts
@@ -21,9 +21,14 @@ import {
   FrontendFeature,
 } from '@backstage/frontend-plugin-api';
 // eslint-disable-next-line @backstage/no-relative-monorepo-imports
-import { toInternalRouteRef } from '../../../frontend-plugin-api/src/routing/RouteRef';
+import {
+  isRouteRef,
+  toInternalRouteRef,
+} from '../../../frontend-plugin-api/src/routing/RouteRef';
 // eslint-disable-next-line @backstage/no-relative-monorepo-imports
 import { toInternalExternalRouteRef } from '../../../frontend-plugin-api/src/routing/ExternalRouteRef';
+// eslint-disable-next-line @backstage/no-relative-monorepo-imports
+import { toInternalSubRouteRef } from '../../../frontend-plugin-api/src/routing/SubRouteRef';
 
 /** @internal */
 export interface RouteRefsById {
@@ -47,9 +52,14 @@ export function collectRouteIds(features: FrontendFeature[]): RouteRefsById {
         throw new Error(`Unexpected duplicate route '${refId}'`);
       }
 
-      const internalRef = toInternalRouteRef(ref);
-      internalRef.setId(refId);
-      routesById.set(refId, ref);
+      if (isRouteRef(ref)) {
+        const internalRef = toInternalRouteRef(ref);
+        internalRef.setId(refId);
+        routesById.set(refId, ref);
+      } else {
+        const internalRef = toInternalSubRouteRef(ref);
+        routesById.set(refId, internalRef);
+      }
     }
     for (const [name, ref] of Object.entries(feature.externalRoutes)) {
       const refId = `plugin.${feature.id}.externalRoutes.${name}`;
diff --git a/packages/frontend-plugin-api/api-report.md b/packages/frontend-plugin-api/api-report.md
index a292634d9a..2260db334f 100644
--- a/packages/frontend-plugin-api/api-report.md
+++ b/packages/frontend-plugin-api/api-report.md
@@ -180,7 +180,7 @@ export type AnyRouteRefParams =
 
 // @public (undocumented)
 export type AnyRoutes = {
-  [name in string]: RouteRef;
+  [name in string]: RouteRef | SubRouteRef;
 };
 
 export { ApiFactory };
diff --git a/packages/frontend-plugin-api/src/wiring/types.ts b/packages/frontend-plugin-api/src/wiring/types.ts
index c2a6b09ba7..7e0650e06c 100644
--- a/packages/frontend-plugin-api/src/wiring/types.ts
+++ b/packages/frontend-plugin-api/src/wiring/types.ts
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import { ExternalRouteRef, RouteRef } from '../routing';
+import { ExternalRouteRef, RouteRef, SubRouteRef } from '../routing';
 
 /**
  * Feature flag configuration.
@@ -27,7 +27,7 @@ export type FeatureFlagConfig = {
 };
 
 /** @public */
-export type AnyRoutes = { [name in string]: RouteRef };
+export type AnyRoutes = { [name in string]: RouteRef | SubRouteRef };
 
 /** @public */
 export type AnyExternalRoutes = { [name in string]: ExternalRouteRef };