There are a lot of private operators offering Siem Reap–Bangkok tickets virtually at every corner in Siem Reap. Sometimes tickets from Siem Reap to Bangkok or Pattaya are sold at as low as USD15. While travelling with these operators you will definitely reach your destination, be aware, though, that your journey may last much longer than expected due to that usual Cambodian perception of ‘good service’. What you will have is likely to be a worn out bus with extremely limited luggage space – actually backpacks and suitcases are piled right in the aisle. Even if nowadays the road between Siem Reap and Poipet boasts quite a decent roadway covering, these buses tend to spend from four to five hours instead of two to reach the border as they call in at a number of souvenir shops and cafes on their way in a hope to wheedle some dollars out of your pockets. No use in arguing, just take it for granted that your journey will be a long one.
Another inconvenient moment is that you have to change the bus at the Thai side after having gone through all the border formalities. If there are enough people for a big bus, you will travel with much more comfort. Sometimes they use a minibus instead which is a bit less pleasant as drivers of minibuses – God knows why – are notorious for their mad speedy driving, so a ride from the border to the capital is not for a faint-hearted. Leg and luggage space is limited in a minibus, too.
There is a direct international bus from Siem Reap to Bangkok operated by Siem Reap Transport Co. It leaves daily at 8am from the office of Nattakan Cambodia Co., Ltd. (22 Sivatha Road). They provide VIP buses which are generally in good condition, but note that there is not too much leg space for a Western traveller. Otherwise buses are quite comfortable, there is a toilet on board and two meals – a small breakfast and lunch – are served during the trip. Do not expect too much from your meals, though – breakfast is a muffin with orange juice or milk, and the lunchbox contains rice with some sort of a curry. International bus tickets from Siem Reap to Bangkok are more expensive than those from Bangkok to Siem Reap and cost THB1149. The main advantage of the international bus is that you do not need to change it at the border which is the case if you book two separate trips – from Siem Reap to Poipet and from Aranyaprathet to Bangkok. Travel time is about eight hours but sometimes the queues at the border crossing both at the Cambodian and Thai sides are endless, so be ready to sweat for a couple hours under the scorching sun. In Bangkok, the international bus arrives to the Northern bus terminal, Morchit, which is located at the northern outskirts of the city. It is linked with the centre of Bangkok by BTS and with both international airports of Bangkok by bus.
As mentioned above, you can opt for two separate trips – from Siem Reap to the border (Poipet) and from the border (Aranyaprathet) to Bangkok. It may take a bit longer than if travelling by the international bus, but you can start from Siem Reap later that the international bus departs. The best way to get to Poipet is by a shared taxi (about USD40 per car). When on the Thai side, take a bus from Aranyaprathet to Bangkok. Aranyaprathet’s bus station is located 6 km from the border, so you will need a tuk-tuk to get there after you have got your permission to enter Thailand. There is also a Rong Klua Market bus station right by the border. Aran bus company offers both express and VIP24 buses from the Aranyaprathet and Rong Klua Market bus stations heading to Bangkok throughout the day. Tickets cost from THB238 to THB254, travel time to Bangkok is from 3½ hours to 5¼ hours. Buses arrive to Morchit, the Northern Bus Terminal.
Tip: Poipet–Aranyaprathet border crossing is open daily from 7am till 10pm, but if you are going to take a bus to Bangkok from Aranyaprathet the same day, note that you have to arrive to the Rong Klua Market bus station by 5pm or to the city bus station by 5.30pm. Otherwise you will have to sleep in Aranyaprathet and continue your journey the next day.