The boy is 13 and he resides with you. That’s fine. At that age the family law courts in the UK (and I’m sure it’s anywhere) give a lot of attention to the child’s wishes on which parent he/she wishes to reside with. The boy will be 16 in less than three years. I would hope he has good contact with his mother also. So your Thai ex-wife lives in the UK and you are thinking of moving with the boy to Thailand? You would want to make sure you give your son the best upbringing and the best education wherever you live, whether it be the UK or Thailand.  (Your assets or prenuptial are irrelevant here.)

@Gaius ********

irrelevant here. He’s asking for Visa/ immigration advice not marriage advice. 

@Stuart ********

well, it’s the only printed information I’ve found, and I keep it on my phone just in case.

It’s six times a year by air.  Four times a year by overland crossing

Oh, very nice. Do you speak Thai? 

@Frances *******

I don’t understand this “deductible“ thing.  Seems to be an American issue.

@Andrew ********

30 day limit on all policies

@David *******

it’s currently-(at least a few months ago when I checked,) showing up on the Thai London Embassy website.

Take a look at this. The first part is obviously out of date. It’s six times per year by flight but only twice a year by overland crossing.

@Sonny *****

that seems to be correct. But many people have said they’re not strict about it at the borders.