There is a twice a day train from Bangkok to Aranyaprathet, which is the closet train station to the Thailand / Cambodia border crossing at Poipet.
Once you arrive at Aranyaprathet station, it is around 5 kilometres to the border control area, which can be easily done by either motorbike taxi or Tuk Tuk from the station, costing around 50 to 100 Baht, depending on which transport you choose.
Once across the border you can continue onto the popular tourist destination of Siem Reap, where the world famous Angkor Wat is located.
In the future, you will be able to travel from Bangkok to Cambodia by train all the way, as the whole of the Cambodian railways, is being rebuilt and that includes the connection of the line across the border into Thailand.
Trains leave from and arrive at Bangkok's main railway station Hua Lamphong.
You can also board or alight these trains from other smaller, but more central Bangkok railway stations, that may be closer to where you are staying.
They are :
If you are looking for the cheapest way to travel from Bangkok to Cambodia's border at Poipet, this is it.
As all the above services are the cheapest "Ordinary" trains and only have 3rd class seats available, they are very cheap.
The train tickets in either direction cost just 48 Baht.
You can't pre-book your seats on these Ordinary trains, so just turn up at the station and buy your tickets.
The trains are quite a bit slower than the public buses that leave from the Northern Bus Terminal at Mo Chit, but it is quite an enjoyable journey and if you have never been on one of Thailand's "Ordinary trains" we would highly recommend this journey.
If you decide to take the faster afternoon train from Bangkok, there are a few places to stay near to the train station, with a number of cheap guest houses along the main road and a few more upmarket hotels scattered around town.
If you decide to cross the border and stay in Poipet for the night, be warned - most of the accommodation is in upmarket casino's which dominate the Cambodian side of the border area.
The times and fares on this page were correct at time of publication, but can change without notice, so please check before travelling by either visiting your nearest railway station in Thailand, telephoning the SRT hotline on 1690 or by checking the Thai Railways official website.