diff --git a/packages/core-compat-api/api-report.md b/packages/core-compat-api/api-report.md
index be80ca50e9..3cd78e6f30 100644
--- a/packages/core-compat-api/api-report.md
+++ b/packages/core-compat-api/api-report.md
@@ -44,6 +44,24 @@ export function convertLegacyRouteRef<
   ref: ExternalRouteRef<TParams, TOptional>,
 ): ExternalRouteRef_2<TParams, TOptional>;
 
+// @public
+export function convertLegacyRouteRef<TParams extends AnyRouteRefParams>(
+  ref: RouteRef_2<TParams>,
+): RouteRef<TParams>;
+
+// @public
+export function convertLegacyRouteRef<TParams extends AnyRouteRefParams>(
+  ref: SubRouteRef_2<TParams>,
+): SubRouteRef<TParams>;
+
+// @public
+export function convertLegacyRouteRef<
+  TParams extends AnyRouteRefParams,
+  TOptional extends boolean,
+>(
+  ref: ExternalRouteRef_2<TParams, TOptional>,
+): ExternalRouteRef<TParams, TOptional>;
+
 // @public
 export function convertLegacyRouteRefs<
   TRefs extends {
diff --git a/packages/core-compat-api/src/convertLegacyRouteRef.test.ts b/packages/core-compat-api/src/convertLegacyRouteRef.test.ts
index 3681d0d2d9..bf82d1e034 100644
--- a/packages/core-compat-api/src/convertLegacyRouteRef.test.ts
+++ b/packages/core-compat-api/src/convertLegacyRouteRef.test.ts
@@ -15,6 +15,9 @@
  */
 
 import {
+  RouteRef as OldRouteRef,
+  SubRouteRef as OldSubRouteRef,
+  ExternalRouteRef as OldExternalRouteRef,
   createRouteRef as createOldRouteRef,
   createSubRouteRef as createOldSubRouteRef,
   createExternalRouteRef as createOldExternalRouteRef,
@@ -23,6 +26,9 @@ import {
   RouteRef as NewRouteRef,
   SubRouteRef as NewSubRouteRef,
   ExternalRouteRef as NewExternalRouteRef,
+  createRouteRef as createNewRouteRef,
+  createSubRouteRef as createNewSubRouteRef,
+  createExternalRouteRef as createNewExternalRouteRef,
 } from '@backstage/frontend-plugin-api';
 import { convertLegacyRouteRef } from './convertLegacyRouteRef';
 
@@ -70,6 +76,15 @@ describe('convertLegacyRouteRef', () => {
     const ref3Converted: NewExternalRouteRef = convertLegacyRouteRef(ref3);
     const ref4Converted: NewExternalRouteRef = convertLegacyRouteRef(ref4);
 
+    // Check for reference equality
+    expect(ref1).toBe(ref1Converted);
+    expect(ref2).toBe(ref2Converted);
+    expect(ref1sub1).toBe(ref1sub1Converted);
+    expect(ref1sub2).toBe(ref1sub2Converted);
+    expect(ref2sub1).toBe(ref2sub1Converted);
+    expect(ref3).toBe(ref3Converted);
+    expect(ref4).toBe(ref4Converted);
+
     const ref1Internal = toInternalNewRouteRef(ref1Converted);
     const ref2Internal = toInternalNewRouteRef(ref2Converted);
     const ref1sub1Internal = toInternalNewSubRouteRef(ref1sub1Converted);
@@ -116,4 +131,76 @@ describe('convertLegacyRouteRef', () => {
     expect(ref4Internal.getParams()).toEqual(['p1', 'p2']);
     expect(ref4Internal.optional).toBe(true);
   });
+
+  it('converts new to old', () => {
+    const ref1 = createNewRouteRef();
+    const ref2 = createNewRouteRef({ params: ['p1', 'p2'] });
+    const ref1sub1 = createNewSubRouteRef({
+      parent: ref1,
+      path: '/sub1',
+    });
+    const ref1sub2 = createNewSubRouteRef({
+      parent: ref1,
+      path: '/sub2/:p3',
+    });
+    const ref2sub1 = createNewSubRouteRef({
+      parent: ref2,
+      path: '/sub1/:p3',
+    });
+    const ref3 = createNewExternalRouteRef();
+    const ref4 = createNewExternalRouteRef({
+      optional: true,
+      defaultTarget: 'ref2',
+      params: ['p1', 'p2'],
+    });
+
+    const ref1Converted: OldRouteRef = convertLegacyRouteRef(ref1);
+    const ref2Converted: OldRouteRef = convertLegacyRouteRef(ref2);
+    const ref1sub1Converted: OldSubRouteRef = convertLegacyRouteRef(ref1sub1);
+    const ref1sub2Converted: OldSubRouteRef = convertLegacyRouteRef(ref1sub2);
+    const ref2sub1Converted: OldSubRouteRef = convertLegacyRouteRef(ref2sub1);
+    const ref3Converted: OldExternalRouteRef = convertLegacyRouteRef(ref3);
+    const ref4Converted: OldExternalRouteRef = convertLegacyRouteRef(ref4);
+
+    // Check for reference equality
+    expect(ref1).toBe(ref1Converted);
+    expect(ref2).toBe(ref2Converted);
+    expect(ref1sub1).toBe(ref1sub1Converted);
+    expect(ref1sub2).toBe(ref1sub2Converted);
+    expect(ref2sub1).toBe(ref2sub1Converted);
+    expect(ref3).toBe(ref3Converted);
+    expect(ref4).toBe(ref4Converted);
+
+    expect(String(ref1Converted)).toMatch(/^RouteRef\{created at '.*'\}$/);
+    expect(ref1Converted.params).toEqual([]);
+    expect(String(ref2Converted)).toMatch(/^RouteRef\{created at '.*'\}$/);
+    expect(ref2Converted.params).toEqual(['p1', 'p2']);
+
+    expect(String(ref1sub1Converted)).toMatch(
+      /^SubRouteRef\{at \/sub1 with parent created at '.*'\}$/,
+    );
+    expect(ref1sub1Converted.params).toEqual([]);
+    expect(ref1sub1Converted.parent).toBe(ref1);
+    expect(String(ref1sub2Converted)).toMatch(
+      /^SubRouteRef\{at \/sub2\/:p3 with parent created at '.*'\}$/,
+    );
+    expect(ref1sub2Converted.params).toEqual(['p3']);
+    expect(ref1sub2Converted.parent).toBe(ref1);
+    expect(String(ref2sub1Converted)).toMatch(
+      /^SubRouteRef\{at \/sub1\/:p3 with parent created at '.*'\}$/,
+    );
+    expect(ref2sub1Converted.params).toEqual(['p1', 'p2', 'p3']);
+    expect(ref2sub1Converted.parent).toBe(ref2);
+
+    expect(String(ref3Converted)).toMatch(
+      /^ExternalRouteRef\{created at '.*'\}$/,
+    );
+    expect(ref3Converted.params).toEqual([]);
+    expect(ref3Converted.optional).toBe(false);
+    expect(String(ref4Converted)).toMatch(
+      /^ExternalRouteRef\{created at '.*'\}$/,
+    );
+    expect(ref4Converted.params).toEqual(['p1', 'p2']);
+    expect(ref4Converted.optional).toBe(true);
+  });
 });
diff --git a/packages/core-compat-api/src/convertLegacyRouteRef.ts b/packages/core-compat-api/src/convertLegacyRouteRef.ts
index c967f9e9b5..24c589bb87 100644
--- a/packages/core-compat-api/src/convertLegacyRouteRef.ts
+++ b/packages/core-compat-api/src/convertLegacyRouteRef.ts
@@ -116,16 +116,113 @@ export function convertLegacyRouteRef<
   ref: LegacyExternalRouteRef<TParams, TOptional>,
 ): ExternalRouteRef<TParams, TOptional>;
 
+/**
+ * A temporary helper to convert a new route ref to the legacy system.
+ *
+ * @public
+ * @remarks
+ *
+ * In the future the legacy createRouteRef will instead create refs compatible with both systems.
+ */
+export function convertLegacyRouteRef<TParams extends AnyRouteRefParams>(
+  ref: RouteRef<TParams>,
+): LegacyRouteRef<TParams>;
+
+/**
+ * A temporary helper to convert a new sub route ref to the legacy system.
+ *
+ * @public
+ * @remarks
+ *
+ * In the future the legacy createSubRouteRef will instead create refs compatible with both systems.
+ */
+export function convertLegacyRouteRef<TParams extends AnyRouteRefParams>(
+  ref: SubRouteRef<TParams>,
+): LegacySubRouteRef<TParams>;
+
+/**
+ * A temporary helper to convert a new external route ref to the legacy system.
+ *
+ * @public
+ * @remarks
+ *
+ * In the future the legacy createExternalRouteRef will instead create refs compatible with both systems.
+ */
+export function convertLegacyRouteRef<
+  TParams extends AnyRouteRefParams,
+  TOptional extends boolean,
+>(
+  ref: ExternalRouteRef<TParams, TOptional>,
+): LegacyExternalRouteRef<TParams, TOptional>;
 export function convertLegacyRouteRef(
-  ref: LegacyRouteRef | LegacySubRouteRef | LegacyExternalRouteRef,
-): RouteRef | SubRouteRef | ExternalRouteRef {
+  ref:
+    | LegacyRouteRef
+    | LegacySubRouteRef
+    | LegacyExternalRouteRef
+    | RouteRef
+    | SubRouteRef
+    | ExternalRouteRef,
+):
+  | RouteRef
+  | SubRouteRef
+  | ExternalRouteRef
+  | LegacyRouteRef
+  | LegacySubRouteRef
+  | LegacyExternalRouteRef {
+  const isNew = '$$type' in ref;
+  const oldType = (ref as unknown as { [routeRefType]: unknown })[routeRefType];
+
   // Ref has already been converted
-  if ('$$type' in ref) {
-    return ref as unknown as RouteRef | SubRouteRef | ExternalRouteRef;
+  if (isNew && oldType) {
+    return ref as any;
   }
 
-  const type = (ref as unknown as { [routeRefType]: unknown })[routeRefType];
+  if (isNew) {
+    return convertNewToOld(
+      ref as unknown as RouteRef | SubRouteRef | ExternalRouteRef,
+    );
+  }
 
+  return convertOldToNew(ref, oldType);
+}
+
+function convertNewToOld(
+  ref: RouteRef | SubRouteRef | ExternalRouteRef,
+): LegacyRouteRef | LegacySubRouteRef | LegacyExternalRouteRef {
+  if (ref.$$type === '@backstage/RouteRef') {
+    const newRef = toInternalRouteRef(ref);
+    return Object.assign(ref, {
+      [routeRefType]: 'absolute',
+      params: newRef.getParams(),
+      title: newRef.getDescription(),
+    } as Omit<LegacyRouteRef, '$$routeRefType'>) as unknown as LegacyRouteRef;
+  }
+  if (ref.$$type === '@backstage/SubRouteRef') {
+    const newRef = toInternalSubRouteRef(ref);
+    return Object.assign(ref, {
+      [routeRefType]: 'sub',
+      parent: convertLegacyRouteRef(newRef.getParent()),
+      params: newRef.getParams(),
+    } as Omit<LegacySubRouteRef, '$$routeRefType' | 'path'>) as unknown as LegacySubRouteRef;
+  }
+  if (ref.$$type === '@backstage/ExternalRouteRef') {
+    const newRef = toInternalExternalRouteRef(ref);
+    return Object.assign(ref, {
+      [routeRefType]: 'external',
+      params: newRef.getParams(),
+      defaultTarget: newRef.getDefaultTarget(),
+    } as Omit<LegacyExternalRouteRef, '$$routeRefType' | 'optional'>) as unknown as LegacyExternalRouteRef;
+  }
+
+  throw new Error(
+    `Failed to convert route ref, unknown type '${(ref as any).$$type}'`,
+  );
+}
+
+function convertOldToNew(
+  ref: LegacyRouteRef | LegacySubRouteRef | LegacyExternalRouteRef,
+  type: unknown,
+): RouteRef | SubRouteRef | ExternalRouteRef {
   if (type === 'absolute') {
     const legacyRef = ref as LegacyRouteRef;
     const legacyRefStr = String(legacyRef);