diff --git a/src/modules/container-loading/components/OceanBookingLinkDialog.test.ts b/src/modules/container-loading/components/OceanBookingLinkDialog.test.ts
index 21ad88d8..2f04920a 100644
--- a/src/modules/container-loading/components/OceanBookingLinkDialog.test.ts
+++ b/src/modules/container-loading/components/OceanBookingLinkDialog.test.ts
@@ -57,4 +57,23 @@ describe('OceanBookingLinkDialog', () => {
     expect(wrapper.emitted('linked')).toHaveLength(1)
     wrapper.unmount()
   })
+
+  it('prefills and preserves a real container number recorded before booking linkage', async () => {
+    const existingContainer = { ...container, containerNo: 'MSCU6639870' }
+    const wrapper = mount(OceanBookingLinkDialog, {
+      props: { modelValue: true, container: existingContainer },
+      global: { plugins: [ElementPlus] },
+    })
+    await flushPromises()
+    const vm = wrapper.vm as unknown as { candidateKey: string; containerNo: string; save: () => Promise<void> }
+    expect(vm.containerNo).toBe('MSCU6639870')
+
+    vm.candidateKey = '101:202'
+    await vm.save()
+
+    expect(linkContainerOceanBooking).toHaveBeenCalledExactlyOnceWith('9001', {
+      oceanBookingId: '101', requirementId: '202', containerNo: 'MSCU6639870', expectedVersion: 7,
+    })
+    wrapper.unmount()
+  })
 })
diff --git a/src/modules/container-loading/components/OceanBookingLinkDialog.vue b/src/modules/container-loading/components/OceanBookingLinkDialog.vue
index d4e9d600..91633f8b 100644
--- a/src/modules/container-loading/components/OceanBookingLinkDialog.vue
+++ b/src/modules/container-loading/components/OceanBookingLinkDialog.vue
@@ -31,7 +31,7 @@ function close() { emit('update:modelValue', false) }
 async function loadCandidates() {
   const target = props.container
   candidateKey.value = ''
-  containerNo.value = ''
+  containerNo.value = normalizeContainerNo(target?.containerNo)
   candidates.value = []
   error.value = null
   if (!target) return