The calculated distance (air line) between Třinec and Jablonec nad Nisou is approximately 171 miles respectively 275 kilometers.
By car or train, the actual journey to Jablonec nad Nisou is certainly longer, as only the direct route (as the crow flies) between Třinec and Jablonec nad Nisou has been calculated here.
Air line (approximately)
275 kilometers
148 nautical miles