diff --git a/src/get-rates-with-shipment-details/format-response.ts b/src/get-rates-with-shipment-details/format-response.ts
index 02093fdd..1bac691b 100644
--- a/src/get-rates-with-shipment-details/format-response.ts
+++ b/src/get-rates-with-shipment-details/format-response.ts
@@ -240,9 +240,9 @@ function formatCustoms(
   customs: Response.InternationalShipmentOptions
 ): GetRatesWithShipmentDetailsTypes.Result["customs"] | null {
   return {
-    contents: customs.contents,
-    nonDelivery: customs.non_delivery,
-    customsItems: customs.customs_items
+    contents: customs?.contents,
+    nonDelivery: customs?.non_delivery,
+    customsItems: customs?.customs_items
       ? formatCustomsItems(customs.customs_items)
       : null,
   };