The calculated distance (air line) between Tuam and Dún Laoghaire is approximately 113 miles respectively 182 kilometers.
By car or train, the actual journey to Dún Laoghaire is certainly longer, as only the direct route (as the crow flies) between Tuam and Dún Laoghaire has been calculated here.
Air line (approximately)
182 kilometers
98 nautical miles