The calculated distance (air line) between Llantwit Major and Porthcawl is approximately 10 miles respectively 17 kilometers.
By car or train, the actual journey to Porthcawl is certainly longer, as only the direct route (as the crow flies) between Llantwit Major and Porthcawl has been calculated here.
Air line (approximately)
17 kilometers
9 nautical miles