Anyone know what happens if I apply for a visa extension (I am on a spouse visa) and then leave the country temporarily and am still outside Thailand when the visa application is decided or when my current visa ends?

If you are not here at the end of the under consideration period your extension application would be voided.

You would have to get re-entry permit for the 30 day under consideration period.

 

As Joe says.

 

Get a re-entry permit.

 

You MUST be back (and able to attend immigration) for the end of the "under consideration" period.

 

In the past (pre-covid) I've arrived with 1 day left on my re-entry permit, immigration chap asked if I really wanted just 1 day, "yes, I'm going to immigration tomorrow", stamp stamp!!

9 minutes ago, Crossy said:

As Joe says.

 

Get a re-entry permit.

 

You MUST be back (and able to attend immigration) for the end of the "under consideration" period.

 

In

Same experience here, though in my case,I returned with two days left.

Thanks. I'll organize my travel accordingly.

2 hours ago, MrDetUdom said:

Thanks. I'll organize my travel accordingly.

 

If, for whatever reason, this does not prove possible, just bear in mind that there is always the option of starting afresh with a real genuine McCoy single-entry visa of the non-O variety for marriage (as distinct from an extension of stay masquerading as one!) obtained from a Royal Thai embassy or official consulate in your home country (assuming that that will be your destination). Upon your return to Thailand you will then be granted a permission of stay of 90 days, and, from 30 days before this expiring (or 45 days if your local immigration office is Chaengwattana or Chiang Mai), apply for your next annual marriage extension of stay.