diff --git a/apps/edr-freight-api/src/modules/bookings/booking-transition.service.ts b/apps/edr-freight-api/src/modules/bookings/booking-transition.service.ts
index 35fc7fd54..06edbf04e 100644
--- a/apps/edr-freight-api/src/modules/bookings/booking-transition.service.ts
+++ b/apps/edr-freight-api/src/modules/bookings/booking-transition.service.ts
@@ -1086,6 +1086,9 @@ export class BookingTransitionService {
         offeredAmount: number;
         paymentDeadline: Date;
       } | null;
+      /** Flat list of physical container numbers on this booking (for the
+       *  customer truck-assignment container picker). */
+      containerNumbers: string[];
     }
   > {
     // This enrichment runs AFTER the transition has committed. A failure here
@@ -1141,12 +1144,20 @@ export class BookingTransitionService {
         `enrichBookingResponse: batch-offer lookup failed for ${booking.id}: ${(err as Error).message}`,
       );
     }
+    // Physical container numbers entered at booking time (booking_container
+    // units), flattened for the customer truck-assignment container picker.
+    const containerNumbers = (booking.bookingContainers ?? [])
+      .flatMap((bc) => bc.units ?? [])
+      .map((unit) => unit.containerNumber)
+      .filter((n): n is string => Boolean(n));
+
     return {
       ...booking,
       latestChangeRequestNote: note?.note ?? null,
       contractSummary: summary,
       nextStep,
       activeBatchOffer,
+      containerNumbers,
     };
   }
 }
diff --git a/apps/edr-freight-web/portal/src/pages/bookings/BookingDetailPage/components/CustomerTruckAssignmentCard.tsx b/apps/edr-freight-web/portal/src/pages/bookings/BookingDetailPage/components/CustomerTruckAssignmentCard.tsx
index 37e65ab2b..c6ec6bf5d 100644
--- a/apps/edr-freight-web/portal/src/pages/bookings/BookingDetailPage/components/CustomerTruckAssignmentCard.tsx
+++ b/apps/edr-freight-web/portal/src/pages/bookings/BookingDetailPage/components/CustomerTruckAssignmentCard.tsx
@@ -38,6 +38,11 @@ export function CustomerTruckAssignmentCard({
   );
   const [error, setError] = useState<string | null>(null);
 
+  // Physical container numbers on this booking — the customer picks which one to
+  // load onto the truck instead of typing it. Falls back to free entry when the
+  // booking has no container numbers recorded.
+  const containerOptions = booking.containerNumbers ?? [];
+
   const assignMutation = useMutation(api.bookings.assignCustomerTruck.mutationOptions());
   const downloadMutation = useMutation(api.bookings.downloadCustomerTruckFreightOrder.mutationOptions());
 
@@ -120,13 +125,27 @@ export function CustomerTruckAssignmentCard({
             onChange={(value) => setTruckType(value ?? "")}
             disabled={assigned}
           />
-          <TextInput
-            label="Container Number to Load"
-            required
-            value={containerNumberToLoad}
-            onChange={(e) => setContainerNumberToLoad(e.currentTarget.value.toUpperCase())}
-            readOnly={assigned}
-          />
+          {containerOptions.length > 0 ? (
+            <Select
+              label="Container Number to Load"
+              required
+              placeholder="Select a container from this booking"
+              data={containerOptions}
+              value={containerNumberToLoad || null}
+              onChange={(value) => setContainerNumberToLoad(value ?? "")}
+              searchable
+              disabled={assigned}
+              nothingFoundMessage="No matching container"
+            />
+          ) : (
+            <TextInput
+              label="Container Number to Load"
+              required
+              value={containerNumberToLoad}
+              onChange={(e) => setContainerNumberToLoad(e.currentTarget.value.toUpperCase())}
+              readOnly={assigned}
+            />
+          )}
         </SimpleGrid>
 
         <Group justify="flex-end">
diff --git a/packages/types/src/freight/index.ts b/packages/types/src/freight/index.ts
index 3afc21a43..705439904 100644
--- a/packages/types/src/freight/index.ts
+++ b/packages/types/src/freight/index.ts
@@ -466,6 +466,10 @@ export interface IBooking extends BaseEntity {
 
   containers?: Array<{ type: string; qty: number; vgm: number }> | null;
 
+  /** Physical container numbers on this booking (from booking container units),
+   *  surfaced for the customer truck-assignment container picker. */
+  containerNumbers?: string[] | null;
+
   versionNumber: number;
   priorityScore: number;