ISA season 2026: your last-minute checklist

Every UK resident over 18 gets a £20,000 ISA allowance per tax year, and if you don't use it by 5 April 2027, it's gone forever. Unlike pension allowances, ISA allowances cannot be carried forward. Many adults never pay into an ISA at all, and leave tax-free returns on the table every year. Even partial use of your allowance can generate meaningful tax-free income. For example, on £10,000 at an illustrative 4% you'd earn £400 completely free of income tax, whereas outside an ISA a higher-rate taxpayer would pay 40% tax on everything above their £500 Personal Savings Allowance. This tax year also matters more than usual for cash savers: from 6 April 2027, if you're under 65 you can only put £12,000 a year into Cash ISAs, so 2026/27 is the last year you can put the full £20,000 into cash.

Before making any moves, you need to know where you stand. Log into every ISA provider you've used this tax year and check your contribution totals. Remember, the £20,000 limit applies across all ISA types combined: Cash ISA, Stocks and Shares ISA, Lifetime ISA (up to £4,000 of the total), and Innovative Finance ISA. A common mistake is forgetting about a small Cash ISA contribution made earlier in the year. Even £100 deposited in April 2026 counts against your 2026/27 allowance. If you've contributed nothing so far, you have the full £20,000 available. Since April 2024 you can pay into more than one ISA of the same type in the same tax year (the exception is the Lifetime ISA, where you can only pay into one a year), so add up contributions across every provider. If your ISA is flexible, money you withdraw can be put back in the same tax year without using more allowance; check with your provider about their flexibility rules.

Not all ISAs are created equal, and the right choice depends on your goals and timeline. Cash ISAs are ideal if you need access to your money within the next one to three years, house deposit, emergency fund, or planned purchase. Rates move with the Bank of England's Bank Rate (3.75% at the time of writing, October 2026), so compare current deals, and your money is protected by the FSCS up to £120,000 per person per authorised firm. Stocks and Shares ISAs make more sense for money you won't need for five or more years. Over longer periods, shares have historically tended to beat cash, though values can fall sharply in the short term and past returns are no guarantee. The Lifetime ISA deserves special mention: if you're aged 18-39, saving for your first home (up to £450,000) or retirement, the 25% government bonus on contributions up to £4,000 per year is one of the best deals in UK personal finance. That is up to £1,000 a year from the government. If you qualify and haven't maxed it out, prioritise this before the deadline.

If you've got spare cash sitting in a current account earning next to nothing, now is the time to move it. Many ISA providers allow instant online applications and same-day or next-day funding. For cash ISAs, many app-based providers process applications within minutes. Fixed-rate ISAs may take longer, so check processing times, some require applications to be received five working days before April 5 to guarantee they count in this tax year. If you don't have a lump sum available, even contributing what you can makes a difference. Depositing £1,000 into a Cash ISA before the deadline means that money starts earning tax-free immediately, and the allowance it uses up would otherwise be lost. For Stocks and Shares ISAs, you can deposit cash now and decide what to invest in later. Most platforms let you hold uninvested cash within the ISA wrapper, preserving your tax-year allowance while you take time to choose your investments.

If you're unhappy with your current ISA rate or provider, an ISA transfer lets you move your money without it counting as a new subscription. This is crucial: withdrawing money from an ISA and redepositing it elsewhere DOES use up your allowance (unless your ISA has flexible features). Always use the formal transfer process. Transfers between Cash ISAs typically take 5-15 working days. Transfers involving Stocks and Shares ISAs can take up to 30 days. Given the April 5 deadline, if you want to transfer AND contribute new money, do the contribution first (to the new provider, if that's where you want to be), then initiate the transfer of old ISA funds separately. The transfer of previous years' ISA money doesn't count towards this year's £20,000 limit. Older ISAs are often left on rates well below the best deals. If that's you, a transfer could significantly boost your returns.

The ISA rules have some gotchas that catch people out every year. First, don't pay into more than one Lifetime ISA in the same tax year. Since April 2024 you can pay into several Cash ISAs or Stocks and Shares ISAs in one year, but only one Lifetime ISA. Second, don't exceed the £20,000 total. Over-contributions can result in HMRC removing the excess from the ISA wrapper and taxing any interest earned on it. Third, Lifetime ISA withdrawal penalties still apply: if you withdraw LISA money for anything other than buying your first home or after age 60, you'll pay a 25% penalty, which means you lose more than the bonus you received. Fourth, don't forget about the LISA age limit. You can only open a Lifetime ISA if you're aged 18-39. If you open one before your 40th birthday, you can keep paying in (and getting the bonus) until you turn 50. If you're 39 and want one, open it before your birthday.

Here is what to do in the last few weeks before 5 April 2027.

• First week: check all existing ISA contributions (our ISA allowance tracker helps), decide on ISA type and open any new accounts.
• Second week: fund your ISA with available cash. Prioritise the Lifetime ISA bonus if you are eligible and it suits your plans, then Cash or Stocks and Shares ISAs.
• Third week: confirm all contributions have landed and check any transfers in progress.
• Final days (1 to 5 April): last-chance contributions. Do not leave it to 5 April itself, as processing delays could mean your money arrives too late.

Even if you can only put in £5,000 of the £20,000 maximum, that is £5,000 earning tax-free returns. To make next year easier, build the habit early: SYM tells you how much to put aside each day and one tap logs it, so your ISA money builds up steadily from April.