There are a/c minivans and non-a/c buses via Prasat to the Chong Chom border pass, 70km south of Surin; or you can arrange a taxi through Farang Connection, located behind Surin bus station. Cambodian visas are issued on arrival at the Chong Chom–O’Smach checkpoint, from where you can get transport to Anlong Veng and then on to Siem Reap, which is 150km from the border crossing (start negotiations for a taxi transfer to Siem Reap at B350/car, but expect to pay slightly more). There have been reports of people on visa runs being asked for more money by officials on the Cambodian side, especially if they try to return to Thailand on the same day. There’s a casino on the Cambodian side, making this crossing popular with Thai gamblers.
Arriving from Cambodia, songthaews and motorbike taxis ferry travellers from the border checkpoint to the bus stop for Prasat and Surin. For details on other overland routes into Cambodia.