Visa on arrival is 100% legitimate. Although your visa application package is submitted to a travel agent and you receive a visa approval letter via email from that agent, your visa approval letter is issued by the Vietnam Immigration Department, not the travel agent. During the time you wait to get the visa approval letter, the travel agent has worked with the Vietnam Immigration Department, submitting your application package to the Department for processing and granting your visa approval letter, receiving the approval letter from the Department and then send it to your registered email. So once you have your visa approval letter, you are ensured to have visa stamped onto your passport if you have full required documents (visa approval letter, passport, 02 passport-sized photos, Vietnamese visa application form and stamping fee).
Especially, the Article 6, Chapter III of the Ordinance No. 24/2000/PL- UBTVQH 10 dated April 28, 2000 on Entry, Exit and Residence of Foreigners in Vietnam specifies that foreigners who enter Vietnam for visit under programs organized by international tour enterprises of Vietnam will have to deal with a travel agent who will forward their visa applications over to the immigration office.
