The first way, All you have to do is just to fill in Vietnam Visa Application form online https://www.vietnamvisaform.com/apply-vietnam-visa
Other way is getting visa in Vietnamese embassy Cambodia:
Embassy of Vietnam
436 Monivong Blvrd, Phnom Penh
Tel: +855-23 362741/+855-23 362741
Fax: +855-23 427 385, 362 314
Tips from other travelers
From many travelers’ experience, it is much more convenient to obtain your visa in Vietnamese consulate in Sihanoukville, because visa will be issued in Sihanoukville. The process takes only 5 minutes and costs around 30USD.
Address: 310 Ekreach- Khan Mittapheap – Sihanouk City
Phone : 349 33 669
Fax :349 33 669
