When should I go to immigration in Koh Chang to extend my Non-Immigrant O visa for 90 days?

you were told wrong. :/ That Non-O visa is sold two ways, a 90 day single entry Non-O <- that gets you stamped in ONCE for 90 days and is done (like you have)

OR

A year long, multi-entry Non-O visa <- where you come into the country get stamped in for 90 days, then when that is running out you exit/re-enter the country to get another 90 day stamp. You do that for the whole year.

The ONLY type of extension based on being over 50 that's available on a Non-O visa is a year extension. There is no 90 day extension .. You apply for the year using the documentation I outlined BUT I'd go to the immigration office and get the hand out (most offices have it) that outlines exactly what you need

@Tod ********

,

@Liss *******

, if im not mistaken, the laem ngop immigration office has been moved to had lek border. I suggest you ask around in koh chang. They have been moving the immigration office around lately...koh chang to laem ngop to trat centre to had lek......

Visa Issues are only done at Laem Ngop immigration office. On the Island only the 90day Reporting.

let's keep it in english please

@Cecilia *****

;) The documents are NOT the same inside the country to get a yearly extension as what she gave at the consulate in Basel to get that visa :/

Liebe Liss, dass ist ein nennen wir es "initial NonImm O" (3 monate/90 Tage)

Du muss 1 Monat vor Ablauf die Verlängerung für einen Jahr beantragen (mit multiple entry!!) Unterlagen sind die Gleiche wie die beim Ansuchen dieses Visum.

@Liss *******

Googling around it appears you go to the Laem Ngop immigration office. BUT on that I'm not 100% sure. sorry.

That is a 90 day single entry Non-O visa, meaning you can come in once for 90 days and then you apply for an extension of stay at the immigration office in your area.

You can apply for the extension when you have 30 days or less left on your current 90 day stamp.

You'd need the letter from the bank, copies of your bank book, update the bank book on the date you're applying for the extension, take your lease, copies of your passport and visa stamps and you should be okay.

You'll get a yearly extension and after you get that you can buy a multiple re-entry permit of you want to

are you using banked money? or are you using a letter from your consulate stating you get income from abroad for the financial requirements?

yep, you got stamped in for 90 days and now that visa is done.