Thai taxes for Brits: leaving HMRC behind, the 1981 treaty and your State Pension
Live in Bangkok for half the year and Thailand can tax your salary and any foreign income you bring in, while HMRC only lets go when the UK rules say so. The treaty between the two is old and thin, and your State Pension stops rising the day you settle here.
The short version
- You're a Thai tax resident if you spend 180 days or more in Thailand in a calendar year. Residents pay tax on Thai income and on foreign income brought into Thailand [5][6].
- Since 1 January 2024, foreign income earned while you're resident is taxable when you bring it into Thailand, whatever year you bring it in. A softer rule has been drafted but wasn't law when we checked [6].
- Leaving the UK tax system is down to the Statutory Residence Test, not your Thai visa. Tell HMRC with a P85 or the SA109 pages of a return [3].
- The 1981 UK–Thailand double taxation convention has no article on private pensions, so both countries can tax them, with credit for the tax paid in the other [1].
- Thailand is not on the DWP's list of countries where the State Pension is uprated, so it's frozen at the rate you get when you move or claim [4].
How Thailand taxes residents
Thai personal income tax runs on the calendar year, not April to April. Your employer in Bangkok withholds tax from your pay each month, and you file an annual return by the end of March after the tax year [5]. Most employees file form PND 91; people with other kinds of income use PND 90. You can file online through the Revenue Department's e-filing service, which usually gives a few extra days beyond the paper deadline. You'll need a tax identification number: Thai nationals use their ID card number, while foreigners without one apply at a local Revenue Department office.
The rates are progressive, from nothing to 35% [7]:
| Net income a year (baht) | Rate | Roughly in pounds |
|---|---|---|
| Up to 150,000 | 0% | up to £3,300 |
| 150,001–300,000 | 5% | £3,300–£6,650 |
| 300,001–500,000 | 10% | £6,650–£11,100 |
| 500,001–750,000 | 15% | £11,100–£16,600 |
| 750,001–1,000,000 | 20% | £16,600–£22,200 |
| 1,000,001–2,000,000 | 25% | £22,200–£44,300 |
| 2,000,001–5,000,000 | 30% | £44,300–£110,800 |
| Over 5,000,000 | 35% | over £110,800 |
Source: Revenue Department rates as published on thailand.go.th [7].
Before the rates apply, you deduct a standard expense allowance on employment income and personal allowances for yourself, a spouse with no income, children and parents. The Revenue Department's own English page still shows older figures, so check the current amounts on its Thai pages or with your employer's payroll team. Social security contributions are deducted separately if you work for a Thai employer, much like National Insurance back home.
What's different from life back home in the UK:
| UK | Thailand | |
|---|---|---|
| Tax year | 6 April to 5 April | Calendar year |
| Residence test | Statutory Residence Test | 180 days or more in the calendar year |
| Foreign income | Arising basis for residents | Taxed when brought into Thailand |
| Annual return | Only if you're in Self Assessment | Most residents with assessable income file |
Foreign income and the 2024 change
For years, Thailand only taxed foreign income if you brought it in during the same year you earned it, so plenty of retirees simply waited until January. From 1 January 2024, under Departmental Instructions Por. 161/2566 and Por. 162/2566, foreign income earned while you're Thai resident is taxable whenever it reaches Thailand. Money earned before 2024 is outside the new rule if you can prove when you earned it [6]. Our guide to Thai tax on foreign income and the 2024 remittance change goes through it properly, including the draft exemption and the LTR visa's carve-out.
Leaving the UK tax system properly
The UK taxes by residence, not citizenship. A Non-O visa stamped in your passport doesn't end UK residence; the Statutory Residence Test does, one tax year at a time.
- Check the automatic overseas tests. Moving for a full-time job in Bangkok? The third automatic overseas test usually fits: full-time work abroad, fewer than 91 days in the UK and fewer than 31 days working more than three hours in the UK. Retiring? Look at the day limits in the Statutory Residence Test explained.
- Look at split-year treatment for the year you go, so that income from your move date is outside UK tax. See split-year treatment.
- Tell HMRC. Use form P85 if you don't normally file a Self Assessment return; otherwise fill in the SA109 residence pages [3]. Our guide to the P85 and your last tax year covers both.
- File on paper or through software. Non-residents can't use HMRC's online services to report their residence. You post a return with the SA109 (deadline 31 October), use commercial software that supports it, or use a tax professional [2].
Bangkok is a long-haul flight from Heathrow or Manchester, so most people don't pop home for weekends. The risk is the long stay: three months back in the UK over Christmas and a family wedding can bring you close to the UK day limits.
The UK–Thailand double taxation convention
The convention was signed on 18 February 1981 and is still the one in force, modified in 2023 by the OECD Multilateral Instrument [1]. The FCDO's Living in Thailand guide says its aim is that you don't pay tax on the same income in both countries [8]. It's older and shorter than most modern treaties, and that matters for pensioners.
| Income | Who can tax it | Article |
|---|---|---|
| Your Bangkok salary, for work done in Thailand | Thailand | 16 |
| Rent from your flat in Leeds | The UK, where the property is; Thailand too if you bring it in | 7 |
| Gains on UK property | The UK; Thailand may also tax | 14 |
| UK government pensions (civil service, forces, NHS and teachers' schemes paid by the state) | Only the UK, unless you're a Thai national living in Thailand | 19(2) |
| UK private and workplace pensions | No specific article, so both can tax | none |
| UK State Pension | No specific article, so both can tax | none |
Source: the 1981 UK–Thailand convention [1].
Residence tie-breaker. If both countries treat you as resident, Article 4 looks first at where you have a permanent home available [1]. Keeping a furnished house in Surrey "for visits" can count against you.
How the relief works. Thailand gives a credit for UK tax paid under the convention on UK income, capped at the Thai tax on that income (Article 23(3)). The UK does the same for Thai tax (Article 23(1)) [1]. Credit relief, not exemption, means you pay at the higher of the two rates. The Revenue Department has an online calculator for the foreign tax credit [9].
The remittance catch. Article 6 says that where one country only taxes income when it's remitted, the other country's relief applies only to the part actually remitted [1]. With Thailand on a remittance basis, that can limit what HMRC will relieve.
A tax adviser who knows both countries can check your situation before you draw a pension or sell UK property. Never move a UK pension to an overseas scheme without regulated financial advice; our guide to UK pensions abroad and the transfer warnings explains why.
Your UK State Pension in Thailand: frozen
This is the sore point. The DWP pays the yearly increase only in the EEA, Switzerland, Gibraltar and countries with a social security agreement that provides for it, and Thailand isn't among them [4]. Your pension is paid at the rate you get when you first claim abroad, or when you leave the UK if you already draw it, and stays there. GOV.UK says it goes up to the current rate if you return to live in the UK [10].
The full new State Pension is £241.30 a week in 2026/27, up from £230.25 in 2025/26 [11]. Someone whose pension froze at the 2025/26 rate misses that £11.05 a week, about £575 (THB 25,900) this year alone, and the gap widens every April. Our guide to the frozen UK State Pension in Thailand runs the long-term numbers and the visa income tests.
On tax: non-residents usually don't pay UK tax on the State Pension [2]. In Thailand it's foreign income, so it's taxable if you're resident and bring it in, with credit for any UK tax.
Other UK income that follows you
- UK rent. Still taxable in the UK. Register for the Non-Resident Landlord Scheme with form NRL1 so rent can be paid without tax taken off, and file a UK return [2].
- Savings and ISAs. You can keep an ISA but can't add to it once non-resident. UK interest is reported to HMRC if taxable [2]. See ISAs when you move abroad.
- Personal Allowance. British citizens keep the UK Personal Allowance as non-residents, so modest UK income may be covered.
Tax comes up most in our community group for Brits in Thailand, usually in February when someone realises their January transfer from Barclays counts as 2026 income.
Pound conversions use the Bank of England spot rate of 5 November 2026 (£1 = THB 45.1092). Tax is general information, not advice.
Sources
- GOV.UK (HMRC): 1981 UK–Thailand Double Taxation Convention and Thailand tax treaties
- GOV.UK: Tax on your UK income if you live abroad (updated 30 September 2026)
- GOV.UK: Tax if you leave the UK to live abroad (updated 30 September 2026)
- GOV.UK (DWP): Countries where we pay an annual increase in the State Pension
- Revenue Department of Thailand: Personal income tax (English)
- Thai Law Online: Thailand foreign income tax 2026, what actually applies (checked October 2026)
- Thailand.go.th: Setting personal income tax rates
- GOV.UK (FCDO): Living in Thailand (updated 11 December 2025)
- Revenue Department of Thailand: Foreign tax credit calculator for personal income tax (updated 2 February 2026)
- GOV.UK: State Pension if you retire abroad, how your pension is affected
- GOV.UK (DWP): Benefit and pension rates 2026 to 2027