VOA — Visa on Arrival
Visa issued on arrival at a Cambodian border post — the airports of Phnom Penh, Siem Reap, Sihanoukville, and several land border crossings with Thailand, Vietnam and Laos. Available to the vast majority of nationalities.
Alternative: the e-Visa requested online before departure, slightly more expensive but avoids the queue on arrival.
For details (fees, duration, extensions), see the Tourist visa guide.