@Wik ****

, You go to the Chaengwattana office at government complex building B. You bring original passport, TM30 receipt on paper (and TM.6 departure card in rare case you issued one at some land borders) along with filled TM.47 form.

Totally depends on the immigration office you go. You need only passport at some immigration office, while you are asked for whole bunch of documents at some other offices, and there are in-between.

You may need all or some of:

Copy of passport (ID page, entry stamp page, related stamps pages), TM30 receipt, latest 90 days report receipt if applicable, TM.6 departure card if applicable, and filled TM47 form

Technically, your business establishment needs specific license for export/import business in Thailand. May depends on volume though.

@Fred *************

, then that was the mistake. You have to go chaengwattana office to get COR.

Chamchuri issues COR for ONLY those who use Chamchuri for visa/extensions. Even if you are on Non-O retirement extension, you cannot get COR at chamchuri office.

If you mean TM.30 submission, the regulation says you have to submit within 24 hours from the time of arrival to the address. <- not from arriving in Thailand.

Check TM.30 online system. There is a User's Manual (in EN and TH) from the link at the bottom of the login window.

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.