Citizens from Brunei, Indonesia, Laos, Malaysia, Myanmar, Phillipines, Seychelles, Singapore, Thailand and Vietnam can visit without a visa for 14 or 30 days.
You may obtain your visa upon arrival at the two airports in Cambodia: Siem Reap and Phnom Penh, along with most border crossings. You will need US$30 cash and one passport size photo and your passport must be valid for six month from the date of entry.
A visa can be issued upon arrival at the border checkpoints into Cambodia. Thailand: Cham Yeam (Koh Kong), Chorm (Oddar Meanchey), Daung (Kamrieng Battambang), Poi Pet (Banteay Meanchey), Prom (Pailin), O Smach (Oddar Meanchey). Vietnam: Bavet (Svay Rieng), Kaoam Samnor (Kandal Mekong), Phnom Den (Takeo), Trapaing Sre (Kratie). Laos: Dong Kralo (Stung Treng). There is also an entry at Sihanoukville if you arrive by sea.
Passport holders from Afghanistan, Algeria, Bangladesh, Iran, Iraq, Pakistan, Saudi Arabia, Sri Lanka and Sudan may need to arrange a visa at an embassy prior to arriving. You may be able to get a visa on arrival but you will need to provide you are a genuine tourist and have a return ticket, hotel booking and proof of funds.
Cambodia visa information
An e-visa service allows you to pay online using a credit card instead of handling cash at the airport. The e-visa is only for use at Phnom Penh International airport, Siem Reap International airport and some of the land borders. It costs seven(7) dollars more than paying cash at the airport.