If Non-ED visa is for studying with an actual school, it is possible to apply inside Thailand at the local immigration office as long as you and the school meet the requirements. But your case is different.

If so, I don't think an in-country Non-ED visa based on internship with a company at the local immigration office is possible. You may need to apply for a Non-ED visa at the RTE/RTCG outside of Thailand.

You need to ask your internship host to contact the local immigration office if it's possible. There might be a recent change.

@T**

would know more details.

So let's make your situation a bit clearer.

You will do an internship with a private company in Thailand, with support from your university in UK. And you are going to apply for Non-ED based on this. Is this correct?

That is no a problem. 90-day reporting window for in-person at the local immigration office is from 15 days before until 7 days after the due date.

You will be fined if you go later than this window.

The day of the week doesn't affect this 3 weeks as it is 3-week's period already.

@Danny *********

, No, you have to wait about 2 months to apply for a 1-year extension.

Most offices accept your long-term extension application when you have 30 days oe less remaining with your stamp. Some including Bangkok, Chiang Mai, and Phuket, accept within the last 45 days with the stamp. A few might have shorter window. But no office has longer window than the last 45 days under normal circumstance.

Q. - this deposit has to be in for 2 months before I can apply.. yes?

If you are applying in Phuket, there is no requirement for a specific period your funds in a Thai bank account for the initial Non-O visa based on retirement.

You can apply for a visa a day after you have a deposit in your Thai bank account.

Two months of seasoning is for a 1-year extension after the initial visa for 90 days.

Also, there is no requirement for mandatory insurance for an in-country Non-O regiment visa application.

That plan sounds okay. It depends on how early you have your funds in Thailand whether process goes to smooth or not. Check with your embassy in Thailand if they issue an affidavit of income. If they do, you can use an embassy letter instead of a deposit in a bank account.

When you enter Thailand on visa-exempt entry, you cannot apply for a 1-year extension directly from the entry stamp.

First. you have to apply for an in-country Non-O visa at the local immigration office for 90 days. Then you will apply for a 1-year extension at the end of that 90-day.

As long as you meet the requirements for in-country procedures, you don't have to leave again.

You need to get the requirements for a Non-O application, too, not for an extension, as some offices have slightly different requirements for a Non-O visa and extension for even the same reason.

Right, at the Chaengwattana office, you will be served within the day as long as you get the number before queueing closes, regardless of how late it could be.

Your entry stamp is no longer valid since you left Thailand.

You will be stamped in for 60 days when you travel to Thailand later.

As you travelled for only two weeks last time, the chance of being questioned at the entry point would be slim (but not zero) unless you have an extensive history of travelling to Thailand.

You can not apply for an extension on any entry/extension stamp from outside Thailand, in any case.

You just need to be back in Thailand on or before the last day of your current extension. Hopefully, several days before to have enough time to prepare necessary documents. There is no rule on how long you can be out of Thailand with a valid extension.

Theoretically, you can re-enter Thailand again on the last day (early enough) with a valid re-entry permit then go to the local immigration office straight to apply for a new extension within the working hours or queueing time if you have everything you need to apply.