Trying to confirm the sense and legitimacy of the following in respect of trying to make the most of a visit to LOS (and after having decided that a visa from the London Embassy is not the way to go, on this occasion) -

·        Arrive in Thailand (as a Brit) without a visa but get a 30 day permit to stay on a visa-exempt basis

·        Before the 30 days are up (as opposed to visiting Immigration to get an extension) make a trip to Mai Sai for a same-day land crossing and re-entry – and get another 30 day permit to stay. (Is this correct?)

·        In due course, and again before the expiry of the second 30 day permit to stay, the plan would then be to either repeat that Mai Sai exercise, or book a return flight to Vietnam and re-enter for another 30 day permit to stay.

Would that work?  Any advice about the current Mae Sai situation would be appreciated.  (I believe for example that land crossings are limited to two per year?)   Thanks in advance for any help. 

Much easier to just obtain a tourist visa before and receive 60 days no need to do the border run.

The crossing at Mae Sai is currently closed, with no prediction of when it might reopen. That aside, three visa exemptions, using two border bounces should, in principle, be no problem (depending on any previous significant immigration history in Thailand).

 

Like others, I feel a single entry tourist visa and one extension at Immigration makes more sense than border bounces, unless you really want to take mini holidays elsewhere (which your intention of using Mae Sai seems to rule out).

Much easier and better to just get an extension to your visa exempt

 

You can only have 2 visa exempt entries per year BY LAND, then you need to either come by air (Risky can be turned away) or get a Tourist visa which is the best option

I would just get a tourist visa for the first 60 days and then do an extension for another 30 days. Far easier that way than doing a visa exempt and border bounce. Then you could do a bounce if you wanted to visit another country or get more time. 

OP, your plan is crazy.

If you enter visa exempt obtain a 30 day extension.

You mention Vietnam.

Excellent option especially if you have visa exempt to Vietnam. 

After return to Thailand visa exempt obtain another 30 day extension.

 

You did not mention how long you wish to stay in Thailand.

Flying is more effective than land borders unless you have a story. A bus trip to Angkor Wat is much more plausible than a one day bounce, particularly to Myanmar. You can do a few exemption entries but they can refuse you at the border at will.

Don't forget entering visa exempt with a return ticket beyond 30 days. Airline probably won't allow you on the flight without showing an onwards ticket within 30 days of your arrival