Surin is straightforward to reach by train from Bangkok. The station sits on the main northeastern line and is served by several daily services from Hua Lamphong station, including an overnight sleeper that departs Bangkok around 10pm and arrives in Surin early the next morning — a comfortable way to travel. Journey time is around 7–8 hours. Ordinary rapid trains are cheap; air-conditioned express trains cost more but are worth it on this long a journey.
Buses also connect Surin to Bangkok's Northern Bus Terminal (Mo Chit). The journey takes around 7 hours on an air-conditioned coach. Several companies run the route, with departures throughout the day and overnight services.
From Buriram, roughly an hour west, you can reach Surin by local bus or minivan. The same applies from Ubon Ratchathani to the east, about 3 hours by bus. For crossing into Cambodia, the Chong Chom border checkpoint is about 70km south of the city; tuk-tuks and minivans can be arranged from Surin town.