The calculated distance (air line) between Kinsale and Dún Laoghaire is approximately 149 miles respectively 240 kilometers.
By car or train, the actual journey to Dún Laoghaire is certainly longer, as only the direct route (as the crow flies) between Kinsale and Dún Laoghaire has been calculated here.
Air line (approximately)
240 kilometers
129 nautical miles