Next to the roundabout are the offices of G.S.T and Angkor Paramount Transport which both run buses to and from Siem Reap (2 hours, $4, twice daily), and Sra Em (1 hour, once daily) for Preah Vihear. Siem Reap bus departs 07:00.
Taxi
Share-taxis and pick-up trucks connect with Siem Reap (2 hours), Samraong (1 hr), Tbeng Meanchey (2 hr) and others. The four main roads to Anlong Veng are now all sealed.
On the Thai side, the international border crossing is at the border of Surin Province and Si Saket Province and is accessible from either. The nearest town is Khu Khan in Si Saket Province. A bus leaves from Moh Chit station in Bangkok at 08:00 and arrives at Ku Khan around 15:00. From there you can hire a motorbike taxi for 400 baht or car to make the hour long journey to the border. This is a border rarely traversed by non-locals and options are limited unless you agree a deal with immigration staff who have the connections. Transport from the Cambodian side/Cho-Am is 700 baht for a car. Probably not the best idea to even try to negotiate the price by walking away as there really is nowhere else to go and the locals know it. Although, from the border post to Anlong Veng is mostly downhill, so if you're up for a pleasant walk, it's not that bad. Walking uphill from Anlong Veng to the border might be a very tiring venture (but possible if you don't mind that sort of thing).
From Surin train station to the border takes about 1.5 hr On the Cambodian side, moto-taxis and pick-up trucks are available in the tiny bazaar
