Theoretical question. You are in a Thai Embassy in the region (Vientiane) applying for lets say a Non B visa, and you see the visa application asks you multiple entry? 5,000 Bhat, less expensive than buying one from immigration in Thailand, but since the embassy will only give you 90 days on the visa before having it extended at immigration, is the multiple entry only good for the first 90 days and would have to be used before then, before the extension would be due?

You would still have to travel to the border every 90 days to keep it alive, surely these costs would need to be added to your hypothetical question. A multi entry from an Embassy or Consulate is normally valid for 12 months and if you use correctly then 15 months

Edited August 9, 201213 yr by beano2274

a single Non-immigrant visa is god for 1 entry into Thailand for a stay of 90 day maximum. A multiple non-immigrant visa is valid for 1 year. During that year you can travel to Thailand an unlimited times, each time you enter you can stay for up to 90 days. By leaving and re-entering just before the visa expires you get another 90 days and so almost 15 days out of it.

A re-entry permit is something entirely different. It keeps your permisison to stay valid when you leave Thailand, and only till the date you were allowed to stay.

a single Non-immigrant visa is god for 1 entry into Thailand for a stay of 90 day maximum. A multiple non-immigrant visa is valid for 1 year. During that year you can travel to Thailand an unlimited times, each time you enter you can stay for up to 90 days. By leaving and re-entering just before the visa expires you get another 90 days and so almost 15 days out of it.

A re-entry permit is something entirely different. It keeps your permisison to stay valid when you leave Thailand, and only till the date you were allowed to stay.

Thanks, in my mind I knew something was not right and I was thinking multiple entry visa=re-entry permits.

The multi entry of a visa would not apply to an extension of stay from immigration - to remain on an extension you would require a re-entry permit.