The most important thing is to make sure your Vietnam visa is stamped with the correct dates and the correct entry and exit points. The standard tourist visa is valid for a period of up to 30 days. If you’re going for less than 30 days you can either specify the exact dates, but it is probably best to ask for the maximum period to give yourself more flexibility. Processing normally takes between a week and ten days (some embassies offer an express service for an extra fee), but longer for overseas Vietnamese. To be on the safe side, allow several weeks as mistakes are common and inexplicable delays often occur.
When applying for a Vietnam visa, in general you have to fill in two application forms and provide two passport photos. One of these forms, with photo attached, will be returned to you with your visa. For some odd reason many people throw this form away. Don’t, because you’ll be asked to hand it in at immigration on arrival. If you don’t have it with you, blank copies are available at immigration. If you’ve got a spare photo, all well and good. If not, you’ll have to engage the services of a handy airport photographer for the princely sum of $2-5.
If you need to extend your stay for any reason, it is relatively easy to apply for a visa renewal at present. Again this is handled by tour agents/travellers’cafés. The first renewal costs around $25-30 (including a handling fee) and takes three working days to process (please note that government offices are only open Monday to Friday). The maximum period you can ask for is 30 days and it costs the same whether you ask for 1 day or 30 days. A second 10-day extension is possible at a cost of around $35-40. For this second extension you will be asked to show an air ticket dated after the expiry of your visa.