I think there are several detailed posts on doing this (either on external blogs or maybe even in this forum). Basically, you take Green Bus ( I did this last week and it was quite easy. I recommend taking the 08:00 bus to Mae Sai and the 15:30 bus back. If you really hustle you might be able to make the 14:30 bus but I wouldn't add the unnecessary worry/stress. Mark mentioned 350 for a VIP seat. I just went with the regular (205) seat each way. The main difference is the VIP seat is much wider. You can also buy your ticket online (pay at 7-11) if you don't want to take an extra trip to the bus station.

Once you arrive at the Mae Sai bus station just hop on one of the red trucks and for 15 baht they will take you directly to the border. That is pretty easy as well. Stamp out of Thailand and walk across the bridge and then pay the entrance fee to Myanmar (US$10 with a crisp, clean bill or 500 THB). They will ask you if you plan to go shopping or not. If you don't want to shop in the local market just say no and they will literally walk you across the street, get your passport stamped and you can turn right around and re-enter Thailand. Whole thing took me about 20 minutes I think. Then look for the red trucks again (parked outside the 7-11) and get back to the station. There is a Tesco near the station (you can get off the red truck close to it) where you can grab lunch if you don't want to look for a place near the border itself. I did everything, including a leisurely stroll around the Tesco after lunch and was back waiting for the bus by 15:00.

@Tod ********

Indeed, very good news for me. Thanks for the clarification.

Tod Daniels Yes, I have saved this post and will report back. My plan is to just see what they do. Worst case, I get the 30 day visa exemption.

Thanks. It might seem I am just being pedantic, but actually I have a multiple entry tourist visa with a Enter Before date of October 23, 2017. I have a flight to China that will leave China October 22 but arrive in Chiang Mai around 1:00 am October 23, so I am actually quite interested in finding out the answer. So, if anyone knows for sure, I would love to hear.

I have a question about the Enter Before date. Somewhere I read or heard that you must actually enter BEFORE that date not up to and including. So, you would have to enter by August 30, 2016 in the sample posted. So, which is it - you can enter August 31 or no later than August 30?

@Tod ********

As I said, I probably misunderstood. :)

@Jeremy *******

I think I probably misunderstood that part so I wouldn't consider that in any way reliable information. Especially since I definitely hadn't done that many in either a calendar year or a 12 month period.

I did it about 4 times (maybe 5 but pretty sure 4) last year and on the last time they showed me some computer screen with something big and red flashing and said I couldn't keep coming and going like that. They let me in but told me the next time I needed to get a proper tourist visa (which I did the next time). They were generally nice about the situation and I didn't completely understand the conversation but I think the concern they were expressing was that the visa exempt doesn't provide any revenue to them so they don't want it overused - better to get the tourist visa. I think they tried to also say something about a limit to the number of times (6?) but I hadn't hit that limit and, again, I might not have understood fully what they were trying to express.