The short answer

When you invest across borders, think about five things besides the investments themselves. Where your money is held, and whether that provider will keep serving a Thai resident. Currency — whether your investments match the currency you'll spend. Tax in both countries, including Thai tax on investment income you bring in. Estate issues, such as US estate tax on US shares and the UK inheritance tax "tail". And cost and custody — what you pay each year and who actually holds your money. Keep pensions in the UK unless there's a clear reason not to, prefer simple low-cost funds, and be very wary of products sold to expats.

Why investing across borders is different

It helps to think of every investment as having two parts. The inside is the investment itself — a share, a bond, a fund. The outside is everything around it: the platform it's held on, the account type, the currency it's priced in, the country where the fund is set up, the country you live in and the country where you'll die. In a purely domestic life, the outside is so stable you barely notice it. In a cross-border life, the outside can matter as much as the inside.

Take a simple example: a fund tracking the world stock market. A UK resident buys it in an ISA on a UK platform, and that's that. A British retiree in Thailand might find that the same fund can't be bought on their UK platform any more; that it's priced in pounds while their spending is in baht; that its income may be taxable in Thailand when brought in; and, if they chose an American-listed version instead, that it could create a US estate tax problem for their family. The investment is identical. The outcome is not.

None of this means investing abroad is risky or complicated in itself. It means you need to look at the outside of each investment as carefully as the inside. The table below gives you a checklist you can use on anything you hold or are offered.

Six questions to ask of every investment

Before you buy — and once a year for everything you already own — ask these six questions.

If you can't answer all six for something you're being offered, don't buy it until you can.

Where you can hold investments as a Thai resident

The first practical problem most British expats meet is access. You may have years of investments on a UK platform — and discover that, once you have a Thai address, you can no longer add money, buy new funds or even keep the account.

UK platforms and ISAs

Policies vary widely. Some UK platforms let non-residents keep existing accounts but not add money; some allow limited dealing; some ask non-residents to leave. ISAs can usually be kept once you're non-resident, but you can't pay new money in. The time to check is before you move, when you still have options. If your platform will keep serving you, an existing ISA can be worth holding: it remains free of UK tax, although Thailand doesn't recognise the ISA wrapper.

International platforms

A number of investment platforms and brokers accept clients living in Thailand. Quality and charges vary enormously, from low-cost brokers with access to thousands of funds and exchange-traded funds, to platforms that mainly exist to sell their own expensive products. Look for clear, low charges, a wide choice of mainstream funds, your money held separately from the firm's own, and an easy way to leave.

Thai investments

Foreigners can open Thai brokerage accounts and buy shares on the Stock Exchange of Thailand, Thai mutual funds and Thai government bonds, though some companies limit foreign ownership and account opening rules vary by firm. Thai investments are naturally in baht, which helps match a baht life. For an individual, gains on SET-listed shares sold on the exchange are tax-exempt, and Thai dividends have 10% tax withheld.

Insurance-based "investment bonds" and savings plans

These are the products most often sold to expats, frequently by people who approach you first. Some have a place for some people, but many carry layers of charges and long lock-ins with heavy penalties for leaving early. We cover them in more detail below.

Your main options compared

A simple comparison of the main places a British expat in Thailand might hold investments. Your own choice depends on your goals, tax position and how much help you want.

The first two are where most expats' long-term money is best held. Fixed deposit tax and SET rules from PwC Worldwide Tax Summaries.

Currency: invest in what you'll spend

Most British expats hold almost all their investments in pounds, because that's where they were built up. But if your life is now in baht, your investments' real value — what they'll buy for you — depends on the exchange rate as well as on markets. A good year for your portfolio can be wiped out by a bad year for the pound, and the other way round.

Your base currency

Start by deciding your base currency: the currency in which you measure whether you're better or worse off. For someone retiring to Thailand for good, that's largely baht. For someone who may return to the UK, it may be a mix. Your base currency decides how much currency risk you should accept.

Match by timescale

Money you'll spend soon — your cash pot and the next few years' income — should mostly be in your spending currency. Long-term growth money can be more international: a global share fund is spread across dozens of currencies anyway, which itself diversifies away from any one currency, including the pound.

Hedged and unhedged funds

Some funds offer "hedged" versions that remove most of the currency movement against a chosen currency. Hedging can make sense for bonds, where currency swings would otherwise swamp the steady returns you're buying them for. For shares, most long-term investors don't hedge. Hedging isn't free: its cost roughly reflects the gap between the two currencies' interest rates, and with UK rates at 3.75% and Thai rates at 1.00% in autumn 2026, the maths of hedging between the two is not simple.

Whatever you decide, the conversions between pounds and baht themselves should be done at a good rate. On a large investment switch, a better exchange rate is worth far more than any small difference in fund charges.

Where to start

A review of what you already hold, a better way to move larger sums between currencies, and a cheap route for everyday money.

Thai tax on your investments

Once you spend 180 days or more in Thailand in a calendar year, you're Thai tax resident for that year. That affects your investments in two ways.

Foreign investment income you bring in

Since 2024, foreign income earned from 2024 onwards that a Thai tax resident brings into Thailand can be taxable here. That can include dividends, interest and gains from investments held abroad, once the money is transferred to Thailand. Savings and investments built up before 2024 are treated differently — but you need to be able to show which money is which. Practical habits help a great deal: keep older money in separate accounts, take income from your investments into a different account from your capital, and keep a log of every transfer to Thailand and what it represents. Our guide to receiving overseas income in Thailand explains the rules.

Thai investments

For investments held in Thailand, the rules are simpler. Dividends from Thai companies have 10% tax withheld, and residents can choose to leave them out of their tax calculation. Interest on Thai bank deposits usually has 15% withheld. Gains on shares listed on the Stock Exchange of Thailand and sold on the exchange are exempt for individuals.

UK tax once you've left

Leaving the UK changes, but doesn't always end, your UK tax position on investments.

• Gains on shares and funds are generally outside UK capital gains tax once you're non-resident — but if you return within five years, gains made while abroad on assets you owned before leaving can be taxed when you come back.
• UK property remains within UK capital gains tax for non-residents, and rent from UK property is still taxable in the UK.
• ISAs stay free of UK tax, but you can't add new money while non-resident.
• Pensions are paid under UK rules and the double tax agreement, which decides where each type of pension is taxed.

The UK–Thailand double tax agreement exists so the same income isn't taxed in full twice. It works best when you know in advance where each kind of income will be taxed and keep the paperwork to claim relief.

Fund domicile and the US estate tax trap

This is one of the least known and most expensive cross-border issues, and it catches many expats who invest for themselves.

If you're not a US citizen or US-domiciled, the United States can still charge estate tax on "US-situs" assets you own when you die. Shares in US companies count as US-situs even if you hold them through a broker outside America. For non-US-domiciled individuals the exemption is only $60,000, and rates go up to 40%. Your family may also need to file US paperwork before they can deal with the assets.

This matters because many low-cost brokers make it easy to buy American shares and US-listed exchange-traded funds. A retiree with a few hundred thousand dollars of US shares could leave their family a sizeable US tax bill and months of paperwork. The UK–US estate tax treaty can give relief to people who are UK-domiciled, but it has to be claimed, and the position of someone living in Thailand needs checking.

The common solution is simple: rather than holding US shares or US-listed funds directly, many expats hold funds based outside the US — for example, in Ireland or Luxembourg — that themselves invest in US and global markets. Before you buy any fund, check where it's based. If you already hold US shares directly, take advice on whether to restructure — this has to be done in your lifetime.

Pensions: why most should stay in the UK

Expats are often encouraged to move their UK pensions into an overseas scheme, known as a QROPS. For someone living in Thailand, that's usually a costly idea.

Transfers to a QROPS face a 25% overseas transfer charge unless an exclusion applies. The main one is that you live in the same country where the QROPS is established. Until 30 October 2024, transfers to schemes in the EEA or Gibraltar were also excluded, but that exclusion has gone for transfers made on or after that date. So for a Thai resident moving a pension to a scheme in, say, Malta or Gibraltar, a quarter of the fund could be lost to the charge before it's invested.

For most British expats, keeping pensions in the UK — in a workplace scheme or a self-invested personal pension (SIPP) that accepts overseas members — is simpler and cheaper. Defined benefit (final salary) pensions are almost always best left alone. If someone recommends a pension transfer, ask exactly what it will cost in total, including any transfer charge, and why it's better than leaving the pension where it is.

Costs: the cross-border tax nobody mentions

Every investment has costs, but cross-border investing can stack them up: a fund charge, a platform charge, an adviser charge, a currency conversion charge, sometimes an insurance-wrapper charge on top. Each looks small as a percentage. Together, compounded over twenty years, they can take a startling share of your money.

The chart at the top of this page shows the effect on £200,000 growing at 5% a year before charges. At a total of 0.5% a year, charges take about £48,000 of growth over twenty years. At 1.5%, about £133,000. At 2.5% — the level some expat savings plans and investment bonds reach once every layer is added — about £203,000: more than the original investment.

• Ask for the total yearly cost of everything — fund, platform, adviser, wrapper — as one percentage.
• Ask for it in pounds too, for your actual investment.
• Ask about one-off costs — entry, exit, switching and currency conversion.
• Compare against a simple low-cost alternative before you agree.

Products sold to expats: what to watch for

Expats are a target market. Some of the people who approach British retirees in Thailand offer genuine help; many sell products that pay them well and you badly. The most common are long-term regular savings plans and single-premium "investment bonds" wrapped in offshore life insurance. They're often described as pensions, tax-efficient or "what all the expats use".

The problems are usually the same: high and layered charges, commission paid up front, and penalties for leaving early that can last for many years. Some people find, years later, that they can't get their money out without losing a large slice of it.

Warning signs include:

1. They contacted you first — by phone, social media or at an event.
2. They won't put the total yearly cost in writing, in pounds.
3. There's a long lock-in or a penalty for stopping early.
4. The return is "guaranteed" or unusually high.
5. You're pressed to decide quickly, or to move a pension.
6. You can't explain what you'd own, or who holds it.

If you already hold one of these products, don't panic and don't cash it in without understanding the cost of leaving. Get an independent look at the numbers first.

Custody, records and what happens when you die

Two final cross-border questions are easy to overlook.

Who actually holds your money?

When you buy through a platform, your investments are usually held by a custodian in a nominee account, separate from the platform's own money. That separation is what protects you if the platform fails. Ask where your investments are held, in which country, in whose name, and what happens if the firm goes out of business. Be very wary of any arrangement where your money is pooled with the firm's own or held somewhere you can't verify.

Can your family find and reach it?

Investments in several countries can be very hard for a family to trace and claim. Keep a list of every account and platform, with contact details, and tell someone you trust where it is. Check beneficiary nominations on pensions and insurance-based products. Make sure your wills cover investments in each country. Remember that UK inheritance tax can follow you for three to ten years after you leave, depending on how long you lived in the UK — and that US estate tax may apply to US shares.

A worked example: Steve and Noi

Steve is British and 58; his wife Noi is Thai. They live in Khon Kaen and plan to stay. Steve has a £220,000 SIPP, a £60,000 stocks and shares ISA, £80,000 in US shares he bought through an online broker, and a regular savings plan he was sold three years ago, paying £500 a month.

Where it's held. His ISA platform lets him keep the account as a non-resident but not add money. He keeps it — it's tax-free in the UK — and opens a low-cost international platform for new money. His SIPP provider accepts overseas members, so the SIPP stays put.

Currency. Their spending is almost entirely in baht. They keep two years of spending in Thai bank deposits and hold their long-term money in global funds, accepting that it isn't all in baht.

US estate tax. Steve's £80,000 of US shares is far above the $60,000 US-situs threshold. On advice, he sells them while he's alive and reinvests through Ireland-based global funds that invest in the same markets, timing the sale and the money he brings to Thailand around his Thai tax position.

The savings plan. An independent look shows total yearly charges of nearly 3% and a large penalty for stopping in the first five years. Steve stops new contributions but leaves the existing money in until the penalty falls away, then plans to move it.

Pensions. He's been told a QROPS would be "more tax-efficient". Living in Thailand, a transfer would face the 25% charge, so the SIPP stays in the UK.

Estate. Wills in both countries, Noi named on his SIPP nomination, and a list of every account kept with their daughter.

Steve hasn't changed his investment approach at all — he still owns a sensible, diversified spread of shares and bonds. What he's changed is the outside: where it's held, what it costs, how it's taxed and what happens when he dies.

The cross-border investment mistakes we see most

1. Not checking the UK platform before leaving, and being forced to sell or move later.
2. Holding US shares directly without realising the US estate tax exposure.
3. Transferring a pension to a QROPS and losing 25% to the overseas transfer charge.
4. Buying a savings plan or bond from someone who made the first approach.
5. Never adding up the total yearly cost across fund, platform, adviser and wrapper.
6. Mixing pre-2024 money with new investment income before bringing it into Thailand.
7. Converting large sums at the bank's rate instead of a specialist's.
8. Leaving no record of where investments are held for the family to find.

Keeping your investment accounts secure

Investment accounts are a prime target for fraudsters, and managing them from abroad means logging in from phones, laptops and shared Wi-Fi. A few habits protect them:

• Use a password manager and a different strong password for every platform.
• Turn on two-factor sign-in everywhere it's offered.
• Use a private, protected connection on hotel, café and condo Wi-Fi.
• Never act on unexpected calls or emails about your investments or pension.

How we researched this guide

We used PwC Worldwide Tax Summaries and the Thai government's guidance on how foreign investors in Thai shares are taxed; our own guide to receiving overseas income in Thailand; KPMG UK on US assets and US estate tax for non-US individuals; the GOV.UK policy paper on reducing tax-free overseas transfers of UK pensions; HaysMac on UK residence-based inheritance tax; and the Bank of England's September 2026 and Bank of Thailand's August 2026 rate decisions. The charges illustration assumes £200,000 growing at 5% a year before charges for 20 years and is not a forecast. Checked 13 October 2026. This guide is general information, not personal financial, tax or legal advice — rules change and individual circumstances differ.