The calculated distance (air line) between Thurles and Dún Laoghaire is approximately 81 miles respectively 131 kilometers.
By car or train, the actual journey to Dún Laoghaire is certainly longer, as only the direct route (as the crow flies) between Thurles and Dún Laoghaire has been calculated here.
Air line (approximately)
131 kilometers
71 nautical miles