Entry stamp classes:

Visa exempt.

Stamp will usually show a stamp ผ.30 but can be handwritten.

On entry you get 30 days and can get one 30 day extension at a local immigration office.

Visa Waiver

Stamp will usually show ผผ.14, ผผ.30 or ผผ.90

On entry you’ll get 14,30 or 90 days depending on nationality. This entry cannot be extended *see extension denial below.

Visa on Arrival

Stamp will usually show TR-15. You’ll know you’ve got this entry as you would have had to pay 2,000 baht for it on arrival.

On arrival you’ll get 15 days. This entry cannot be extended *see extension denial below.

Tourist Visa

Stamp will usually show TR

On arrival you’ll get 60 days and most nationalities can extend once for 30 days at a local immigration office.

If you’re from India, Sri Lanka, Bangladesh, Iran, Nepal, Togo, Nigeria or Uganda you cannot get an extension. *see extension denial below

Non OA or OX

Stamp will show Non OA or OX

You get one or five years on entry.

You’ll know you’ve got this because you will have needed to provide insurance, had a police certificate and a medical to get the visa. Normally only available in your home country or country of legal residence.

You can exit and re-enter as many times as you like on these visas until their expiry date.

Non O or B

Stamp will show Non O or B. Usually these visas are single entry where you’ll get 90 days on entry. Some may be multiple entries valid for one year. You’ll get 90 days on entry.

You can extend these for a year at a time providing you meet the requirements to do so. If not the multiple entry version and you need to leave within the 90 days you’ll need a re-entry permit to keep your current “allowed to stay” date alive.

Non RE

This stamp means that you entered using a re-entry permit. This means that whatever stamp you had prior to entry will determine the time allowed to stay.

PE

Privilege Entry visa. Membership ranges from 5-20 years. On entry you’ll get stamped in for one year at a time, extendable yearly until the life of your membership at a local immigration office.

You’ll know you have this visa as your wallet will be significantly lighter.

LTR

Long Term Resident visa. Pretty new. Haven’t seen many stamps so not completely sure what it’ll say. You're stamped in until the end of your 5 year stamp (not the 10 year stamp) or until the expiration date of your passport.

Extension Denial

If your visa or entry stamp type is not extendable then some offices may allow you to apply for an extension. However this will be denied and you will be given 7 days to leave. Some offices may add on the 7 days to your existing stamp or may date it the from day you apply.

Many offices will require you to have a ticket out of Thailand within the 7 days in order to apply.

You will get a stamp in your passport saying “application for extension denied”. Beware there have been reports that some with this stamp have been refused entry or visas to other countries because of this stamp.

Counting Days

The day you enter Thailand is classed as day 1 regardless of the time you arrive. This means for example that on a Tourist Visa entry you be stamped in for 59 further days. Many people make the mistake thinking that entry day would be day 0 and mistime their onward or return tickets.

What entry stamp will I get?

That depends on your nationality and/or whether you bought a visa prior to arrival. See the infographic in the comments to check yours.

There may be other entry classes that I’ve missed on this list, but they’d be pretty rare as these are the major ones. For example Diplomatic or Government Passports.