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Can I add to a Cash ISA and transfer at maturity?

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UKPublished 6 October 2026 · Written by BuyMeWhiskey Editorial Team · How we check facts

You can add money to a 12-month Cash ISA only if its terms allow further subscriptions. At maturity, you can normally transfer the ISA directly without using fresh allowance. From 6 April 2027, the Cash ISA limit is £12,000 for people under 65.

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Use the GOV.UK ISA transfer process when moving a maturing ISA so its tax-free status and subscription history are preserved.

Transfer an ISA on GOV.UK

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Adding money to a 12-month ISA depends on whether it is open for subscriptions

A fixed or 12-month Cash ISA normally has its own product terms. If the account accepts additional subscriptions, those payments count towards your ISA allowance for the tax year in which you make them. If the product is closed to further subscriptions during the fixed term, you may need to wait for maturity or use a different ISA.

For 2026/27, the overall adult ISA subscription limit is £20,000. That is the limit on new ISA subscriptions across the different adult ISA types, subject to the separate Lifetime ISA limit. You do not get an extra £20,000 for each account.

What happens when the 12 months ends?

At maturity, follow the provider's instructions. You can usually keep the money within an ISA by reinvesting or transferring it, but the contractual options vary. If you transfer an ISA directly using the ISA transfer process, the transferred money keeps its ISA status and does not use your new annual subscription allowance.

GOV.UK says an ISA can be transferred to another provider at any time, including to a different type of ISA, subject to restrictions for Lifetime ISAs and Junior ISAs. A cash-to-cash transfer should take no more than 15 working days according to GOV.UK's transfer guidance.

Does an ISA transfer count as a new ISA?

It is the money being transferred rather than a fresh cash subscription. That is why using the provider's transfer process matters. If you withdraw an ISA yourself and then pay the cash into a different ISA, that is no longer the same as a formal transfer and can create an allowance problem.

What changes from 6 April 2027?

This is particularly relevant to a 12-month ISA maturing in 2027. The government published the ISA reform measure in September 2026. From 6 April 2027, the annual Cash ISA limit will be £12,000 for people under 65, while the overall ISA limit remains £20,000 and the Cash ISA limit remains £20,000 for people aged 65 or over.

The lower £12,000 limit applies to new cash subscriptions. It does not turn an existing £18,000 or £20,000 ISA balance into an amount that must be withdrawn or taxed. Existing ISA savings remain within the ISA wrapper, and direct transfers remain the proper mechanism for moving them between providers.

Do flexible ISA rules change the answer?

A flexible ISA can allow you to withdraw money and replace it during the same tax year without reducing the annual subscription allowance, subject to the provider's terms. Flexibility is optional for providers, so never assume a Cash ISA is flexible just because it allows withdrawals.

What about an ISA opened near 6 April?

Tax years run from 6 April to 5 April. A payment made on 2 April belongs to the earlier tax year, while a payment made on 6 April belongs to the new tax year. Opening an account is not the same as subscribing: the payment date is what matters for the allowance.

Common maturity mistakes

Withdrawing the matured ISA to a normal bank account before arranging the transfer.
Assuming the same account automatically allows new subscriptions when it is a fixed-term product.
Using the £20,000 overall allowance as if it were a £20,000 Cash ISA limit after April 2027.
Forgetting that a Lifetime ISA has a £4,000 annual subscription limit within the overall ISA limit.

Tell the provider what you want before maturity

Fixed-term Cash ISAs often have a maturity process. A provider may offer a notice period, a choice of new fixed terms, or an option to transfer elsewhere. The exact steps are product-specific, so check the maturity notice rather than assuming the money will automatically move to the account you want.

Also keep the tax-year distinction clear. An ISA transfer preserves the existing ISA wrapper, while a new cash subscription uses the current year’s allowance. Separating those two actions avoids the common mistake of treating transferred money as if it were a fresh contribution.

Worked example

Illustrative example: Priya is 58. She has an old Cash ISA worth £18,000 that matures during the 2027/28 tax year. She wants to move the full maturity value to another Cash ISA and add some new money.

Because the £18,000 is an existing ISA balance, a direct ISA transfer moves £18,000 without treating it as a new annual subscription.
For 2027/28, Priya is under 65, so her new Cash ISA subscription limit is £12,000.
If she adds £5,000 of new money to a Cash ISA, that uses £5,000 of the £12,000 cash limit.
Her unused Cash ISA subscription capacity is £12,000 − £5,000 = £7,000.

The £18,000 transfer does not use that £7,000. That is why a proper ISA transfer is important when a fixed-term account matures.

Can I add money to a 12-month fixed Cash ISA before it matures?#

Only if the product terms allow further subscriptions. Some fixed-term ISAs are closed to additional deposits during the term. Check the account terms rather than assuming that an ordinary Cash ISA can always accept more money. Provider terms can set the practical maturity timetable, so check the notice and transfer instructions before the fixed term ends.

Does transferring a Cash ISA use my annual ISA allowance?#

A direct ISA transfer does not count as a new subscription. The existing ISA money keeps its tax-free status while it moves to the new provider. Use the provider's ISA transfer process rather than withdrawing the money to a bank account first.

What is the Cash ISA limit from April 2027?#

From 6 April 2027, the Cash ISA subscription limit is £12,000 for people under 65. The overall ISA limit remains £20,000, and the Cash ISA limit remains £20,000 for people aged 65 or over under the published reform. Provider terms can set the practical maturity timetable, so check the notice and transfer instructions before the fixed term ends.

Can I transfer a maturing ISA into a stocks and shares ISA?#

Generally yes, subject to the ISA type rules and the provider accepting the transfer. GOV.UK says you can transfer an ISA to the same or a different type of ISA, with special restrictions for Lifetime ISAs and Junior ISAs. Provider terms can set the practical maturity timetable, so check the notice and transfer instructions before the fixed term ends.

Does opening an ISA on 2 April and paying in on 6 April use one year or the next?#

The subscription tax year is determined by when the money is paid in. A payment on 2 April falls in the earlier tax year, while a payment on 6 April starts the new tax year. Opening an account by itself does not use the allowance.

Can a flexible ISA restore withdrawn money?#

A flexible ISA can allow withdrawn money to be replaced in the same tax year without using the annual subscription allowance, subject to the provider offering flexibility and the specific replacement rules. A non-flexible ISA does not provide that extra replacement capacity.

How long should a Cash ISA transfer take?#

GOV.UK says transfers between Cash ISAs should take no longer than 15 working days. If a provider takes longer, contact it first and then use its complaints process, with the Financial Ombudsman Service available for eligible disputes. Provider terms can set the practical maturity timetable, so check the notice and transfer instructions before the fixed term ends.

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Next question →What should you do with a LISA after buying a home?

Sources

Figures were checked against these sources before publication. If a rule changes, we update the page and show the new date.

General information, not personal financial advice. Rules depend on your circumstances; check the official source or speak to a regulated adviser before acting.