If you open an Individual Savings Account (ISA) in the UK then move abroad, you cannot put money into it after the tax year that you move (unless you’re a Crown employee working overseas or their spouse or civil partner).
See Also
Tax on bonds and giltsTax Free Investments UK: Best Tax Free Investing | MoneyfarmHow to Invest £20,000 | Investing your first 20KAre NS&I Premium Bonds worth it? - Times Money MentorYou must tell your ISA provider as soon as you stop being a UK resident.
However, you can keep your ISA open and you’ll still get UK tax relief on money and investments held in it.
You can transfer an ISA to another provider even if you are not resident in the UK.
You can pay into your ISA again if you return and become a UK resident (subject to the annual ISA allowance).
