The calculated distance (air line) between Kaštel Sućurac and Vukovar is approximately 178 miles respectively 286 kilometers.
By car or train, the actual journey to Vukovar is certainly longer, as only the direct route (as the crow flies) between Kaštel Sućurac and Vukovar has been calculated here.
Air line (approximately)
286 kilometers
154 nautical miles