diff --git a/api/services/mapping/converters.js b/api/services/mapping/converters.js
index 2e8e867bb..2026f422e 100644
--- a/api/services/mapping/converters.js
+++ b/api/services/mapping/converters.js
@@ -79,7 +79,9 @@ const c = {
     temperature: source.temperature,
     isDiving: source.isDiving,
     nbEntrances: source.nbEntrances ?? source.entrances?.length ?? 0,
-    entrances: source.entrances?.map((e) => e.id),
+    entrances: source.entrances
+      ?.map((e) => e?.id ?? e)
+      .filter((e) => e != null),
   }),
 
   toCaver: (source, meta) => {
diff --git a/test/integration/1_services/Converters.test.js b/test/integration/1_services/Converters.test.js
index 3895b7068..472813b06 100644
--- a/test/integration/1_services/Converters.test.js
+++ b/test/integration/1_services/Converters.test.js
@@ -204,6 +204,59 @@ describe('Converters Service', () => {
       const result = converters.toSimpleCave(source);
       should(result.exploringOrganizations).be.undefined();
     });
+
+    it('should extract entrance IDs from Waterline objects', () => {
+      const source = {
+        id: 1,
+        entrances: [
+          { id: 5, name: 'Entrance A' },
+          { id: 6, name: 'Entrance B' },
+        ],
+      };
+      const result = converters.toSimpleCave(source);
+      should(result.entrances).deepEqual([5, 6]);
+    });
+
+    it('should pass through plain entrance IDs (Typesense format)', () => {
+      const source = {
+        id: 1,
+        nbEntrances: 3,
+        entrances: [20, 21, 25877],
+      };
+      const result = converters.toSimpleCave(source);
+      should(result.entrances).deepEqual([20, 21, 25877]);
+    });
+
+    it('should pass through string entrance IDs', () => {
+      const source = {
+        id: 1,
+        nbEntrances: 2,
+        entrances: ['20', '21'],
+      };
+      const result = converters.toSimpleCave(source);
+      should(result.entrances).deepEqual(['20', '21']);
+    });
+
+    it('should filter out null entries from entrances array', () => {
+      const source = {
+        id: 1,
+        entrances: [{ id: 5 }, null, { id: 6 }, undefined],
+      };
+      const result = converters.toSimpleCave(source);
+      should(result.entrances).deepEqual([5, 6]);
+    });
+
+    it('should return an empty array when entrances is empty', () => {
+      const source = { id: 1, entrances: [] };
+      const result = converters.toSimpleCave(source);
+      should(result.entrances).deepEqual([]);
+    });
+
+    it('should return undefined entrances when field is absent', () => {
+      const source = { id: 1, nbEntrances: 0 };
+      const result = converters.toSimpleCave(source);
+      should(result.entrances).be.undefined();
+    });
   });
 
   describe('toDocument()', () => {