What happens to your UK ISA when you leave the UK

A common assumption among British expats who held ISAs before leaving the UK is that the account closes, or that something must be done to preserve it, on becoming non-resident. Neither is true. An existing ISA stays open after you leave the UK. The funds remain within the wrapper, the investments remain, and nothing requires the account to be closed.

What changes is the fiscal environment the ISA operates in. The UK tax shelter it provides is a feature of UK tax law. Once you are no longer a UK taxpayer on investment income and gains because you are non-resident, that shelter is doing less work than it was. Whether the ISA is still the right place to hold those assets depends on where you are now tax-resident and what that jurisdiction does with the income and growth inside the wrapper.

Inside a UK ISA, income and capital gains are sheltered from UK income tax and UK capital gains tax. For a UK-resident investor that has clear annual value. For a non-resident, the UK tax position on many categories of income from UK investments changes anyway: a non-resident individual is not typically subject to UK income tax on investment income from UK securities in the same way a resident is, subject to specific rules for certain UK-source income. The shelter may therefore be doing work that non-resident rules already do.

What the wrapper does not do is provide any protection from the tax laws of your new country of residence. Thailand, under the 2024 remittance rule, taxes income remitted into the country by Thai tax residents. If dividends or interest generated inside the ISA are remitted to Thailand, the fact they were produced within an ISA wrapper is not a relevant fact under Thai law. Thai tax rules operate entirely independently of UK tax wrappers.

The rule that ends immediately on becoming non-resident is the right to make new ISA contributions. You cannot pay fresh money into a UK ISA in any tax year in which you are non-resident. The existing funds stay in the wrapper and continue to benefit from the UK shelter, but the annual allowance is unavailable until you are UK-resident again.

This matters because the ISA’s value as a long-term accumulation vehicle depends partly on the ability to keep adding to it. A non-resident cannot. The wrapper holds what it holds; future growth and income on those holdings are sheltered, but no new capital is going in.

Some UK investment platforms are straightforward about their position on non-resident ISA holders and will hold and service the existing account as long as UK regulatory and tax rules permit. Others apply restrictions: limits on the investments available to non-residents, restrictions on trading, or a decision to stop servicing non-resident accounts entirely.

The practical step on leaving the UK is to contact your platform and ask directly about its non-resident policy. Not all platforms handle this consistently, and the answer is not always prominent in the account terms. Knowing the platform’s position before you leave, rather than discovering a restriction afterwards, is the more orderly approach.

What to do with an existing ISA as a long-term expat is genuinely open and depends on the individual. There are arguments for keeping it: the funds are sheltered from UK tax, the wrapper is established, and UK investments may form part of a diversified portfolio. There are arguments for reviewing whether the assets inside are the right ones for a cross-border life: a UK-centric equity portfolio inside an ISA, serviced by a platform that may at some point close non-resident accounts, is not a set-and-forget arrangement.

What is clear is that the ISA is not a neutral, costless asset once you have left the UK. It is a UK-resident-optimised structure that requires a non-resident holder to think carefully about currency exposure, platform risk, and the tax treatment of withdrawals or remittances in the new jurisdiction. That review is worth doing once, properly, rather than letting the account drift.

This article describes the framework of how a UK ISA operates for a non-resident holder. It is general information. The specific position depends on your current residency status, domicile, the assets held within the ISA, and the tax rules in your country of residence.

The wealth management service at /en/services/wealth-management covers how existing UK investments and wrappers fit into a cross-border financial plan for expats in Thailand. For a 30-minute conversation about your own position, book at /en/book.