Before you start

A day count for the calendar year, kept as you go
Records of when income was earned as well as when it was remitted
A Thai Tax Identification Number from the Revenue Department

Step-by-step

1
Count your days — 180, not 183
180 or more days in Thailand in a calendar year, consecutive or not, makes you a Thai tax resident for that year. Many people carry a 183-day rule of thumb from elsewhere and miscount by exactly three days. The count resets on 1 January. For a retiree who spends most of the year here, residency is not really in question — but the year you go home for an extended period may change it.
OnlineWho: YouTrack through the yearFree
2
Get a Tax Identification Number
Register with the Revenue Department for a TIN, at a local area office or through your employer's HR if you are employed. You need it to file and to use the e-filing system, and it makes claiming treaty relief on a foreign pension substantially easier. Retirees often assume they need no Thai tax number at all; if you are resident and remitting income, that assumption should be tested rather than adopted.
In personWho: YouSame day to a few daysFree
3
Work out how your pension is treated
A foreign pension remitted into Thailand by a Thai tax resident is within the scope of the post-2024 remittance rules in principle. Whether it is actually taxed here depends on the type of pension, the double taxation agreement between Thailand and the country paying it, and whether the treaty assigns taxing rights to the source country. Treaties differ substantially on government versus private pensions. This is the single most important thing for a Pattaya retiree to establish, and it is genuinely worth paying a Thai adviser to answer for your specific treaty.
OnlineWho: You, with a Thai tax adviserEstablish once, then review annuallyAn adviser's fee, which is small against the exposure
4
Keep dated records of what was earned when
Income earned before 1 January 2024 is outside the remittance rules regardless of when you bring it in. For someone who moved here with accumulated savings that distinction can be worth a great deal, and the only thing that establishes it is dated documentation of when the funds were earned as opposed to when they were transferred. Assemble that now, while statements are easy to obtain.
OnlineWho: YouDo it once, properlyFree
5
File the annual return
Thai personal income tax runs on the calendar year. File PND.91 if your only income is Thai employment, PND.90 if you have other or foreign income. Paper returns are due at the end of March with a short extension for online filing. Employees have tax withheld monthly and still file to reconcile.
OnlineWho: YouFiled January to March following the tax yearFree to file; pay any balance due

Documents you’ll need

Thai Tax Identification Number
Pension statements and any foreign tax certificates
Dated records showing when income was earned and when it was remitted
Employer withholding certificate, if employed in Thailand
Evidence supporting any treaty relief claim

Things most newcomers don’t know

For a Pattaya retiree, how your specific pension is treated under your specific treaty is the most consequential unanswered question in the move.

Since 2024, foreign income earned while you are a Thai tax resident is assessable when you remit it. A pension paid from abroad into a Thai account is squarely the kind of flow that reaches. Whether Thailand actually taxes it turns on the double taxation agreement with the paying country, and those treaties differ sharply — many assign exclusive taxing rights over government service pensions to the source state while treating private pensions differently. There is no general answer, only a treaty-specific one, and the advice fee is trivial against the amount at stake over a retirement.

Source: Revenue Department orders Por. 161/2566 and Por. 162/2566; Thailand's double taxation agreements

Chonburi's position inside the Eastern Economic Corridor makes a 17% flat rate available that Bangkok cannot offer.

Royal Decree No. 641 allows qualifying foreign executives, specialists and researchers working for a targeted-industry business in the EEC to elect a flat 17% rate on employment income instead of the progressive scale reaching 35%, and the EEC's own visa scheme carries the same rate. For a senior professional this is a substantial and structural difference, and it is one of the few genuine reasons to prefer a job in the Chonburi and Rayong corridor over one in the capital. It depends entirely on the employer qualifying — establish that before you accept, not after.

Source: Royal Decree (No. 641) B.E. 2560; EEC visa scheme

Pre-2024 income is grandfathered and only your records prove it.

Foreign income earned before 1 January 2024 is outside the remittance rules whenever you bring it in. For someone who arrived with a lifetime's savings, that distinction can shelter a large sum permanently — but only if you can evidence when the money was earned as opposed to when it moved. Assembling dated statements now, while they are easy to get from a former employer or bank, is far cheaper than trying to reconstruct it during an enquiry a decade later.

Source: Revenue Department orders Por. 161/2566 and Por. 162/2566

Pattaya's condominium market is one of the few in Thailand where the foreign quota is genuinely often still open.

A foreigner may own a condominium unit only within the building's statutory foreign share, measured on aggregate unit floor area — and in the desirable parts of Bangkok that quota is frequently exhausted, so the unit you want simply cannot be sold to you. Pattaya's sheer depth of supply means quota is far more commonly available here. That is a real practical advantage, but it does not change the other rules: land still cannot be foreign-owned, the purchase funds must arrive in foreign currency with the bank's record of the inward remittance, and nominee-shareholder company structures to hold land remain unlawful.

Source: Condominium Act B.E. 2522; Thai land ownership restrictions

Common mistakes to avoid

Assuming a foreign pension is automatically untaxed in Thailand without checking the specific treaty
Using a 183-day rule of thumb when Thailand's residency threshold is 180 days
Failing to document which savings were earned before 2024 and are therefore outside the remittance rules
Assuming the EEC's 17% rate follows from working in Chonburi, when it depends on the employer being a qualifying targeted-industry business
Buying a condominium without confirming the building's foreign quota has room, or remitting the purchase funds in baht
Accepting a nominee-shareholder company structure to hold land, which is unlawful and puts the asset at risk

Some of this may be out of date. Spotted something inaccurate? Help us keep it right for the next newcomer.