From Poipet, Cambodia
To reach Poipet from elsewhere in Cambodia, see the Poipet article. The border crossing opens at 07:00 and closes at 20:00. There's no time difference between Cambodia and Thailand.
Entering Thailand from Poipet is straightforward for travellers entitled to enter without a visa and for those who have obtained a visa in advance.
Nationalities entitled to visa-on-arrival facilities should note that visas are available on arrival when entering Thailand overland from Cambodia, a flight ticket flying out of Thailand and departing from Bangkok plus the 1000 bhat visa fee is required and the visa term is likely to be of 14 days not 15 as they might tell you, be aware of this when you purchase your flight ticket. Note however that various nationalities don't need a visa for a short stay in Thailand. Unfortunately, the visa-free term has been reduced to 15 days for people entering Thailand at a land border. This is a measure against people extending their residence permit in Thailand effectively indefinitely by periodic trips to neighbouring countries. As a compensation againstt this measure, free Thai visa can be obtained at the embassy in your home country.
If you cross from Thailand to Cambodia in the morning, you're likely to see a long line of Thais waiting for an one-day exit stamp to gamble at the casinos in Poipet. However there's a separate line for non-Thais and in a welcome change from usual order of preference, it's quite a bit faster than the one the natives have to use - at least until mid-day, when the Khao San tourist buses arrive.