There are two options as below:
1/ Visit Vietnamese embassy in Bangkok
83/1 Wireless Road, Lumpini, Pathumwan, Bangkok 10330
+ Tel. 66 (0) 2 251 5836-8
+ Fax. 66 (0) 2 251 7203
E-mail: vnemb.th@mofa.gov.vn
Office hours: Monday – Friday: 08.00-11.30 Hrs. and 13.30-16.30 Hrs.
You are required to provide 1-2 passport size photos and the cost was about 1500 Baht. Normal process takes around 2-3 days, if you need an express one (1 working day), then you have to pay a little bit more.
2. Getting visa on arrival
If you travel to Vietnam by air from Thailand, visa on arrival is a convenient method to get your Vietnamese visa online. Our service fee is 18$ US/person and it takes only 2 working days to get it approved.