It is not the same practice in Laos or Cambodia as in Vietnam, applying visa to Vietnam is required before going to Vietnam. Many foreigners are confused with this simple fact which leads to many big problems when entering Viet Nam. I myself got an unforgettable experience when landing to Noi Bai airport without visa. However, luckily I was advised by an online visa consultant agent named http://www.getvisavietnam.com and got my visa within a very short time.
For some reasons, you forget to find out whether Vietnam Government requirement of visa before coming. This omission caused a lot of problems as followings:
1/ Cost much for flight tickets:
+ Some airlines do not check for visa before you get on board, so you can fly to Vietnam international airports in Ha Noi, Da Nang, and Ho Chi Minh City. There, Vietnam Immigration Officer will ask you to show the pre-approval letter. Without it, they will not allow you to enter Vietnam and you must book flight ticket to come back to your country.
+ Some airlines require your visa, so you are not permitted to get on board if you do not have Vietnam visa.
Both the two cases above cost your money which results in your trip will be delayed; hotels will be cancelled, the deposit will be lost. This is so terrible!
2/ Cost much for visa service:
In some cases, when you are at Vietnam International airport and ask for very urgent visa from a travel company in Vietnam, it will cost you more than normal. Keep in mind that you just get it in their working days as the visa service in weekend and holidays is not available. In such cases, they will suggest the special service called Guarantee Service. It is very expensive and even uncertain if you book service through an untrusted company.
From all the issues above, please apply for Vietnam visa in advanced, then the other services (hotels, cars, tours, etc …) for sure if you do not want to lose your trip to this beautiful country.