anyone familiar with vietnamese visa?

[thebestman36]

I kinda got stuck having to do some major plan changes from when I booked our trip tickets this spring. We are coming for 3 months, but we didnt get thai visas because we werent going to be staying over 30 days in thailand, instead going onward to cambo and vietnam. But I didnt realizeback then that we needed proof of onward flight in order to enter thailand without a thai visa. So now Im trying to see where and how long it takes to obtain a vietnamese visa. I'd like to buy it in chiang mai if possible. Pattaya is my other option. Any idea how long it takes and if I can buy one in either city? I'll be in both cities for about a week or so. Thanks!