This guide explains the rules governing Junior ISAs in the UK. It is not financial advice, and tax rules can change.
Overview
A Junior ISA is a tax-free savings or investment account for a child under 18 who lives in the UK. The money belongs to the child from the moment it is paid in, which is the single fact that explains most of the other rules — including the ones people find frustrating.
Junior ISAs sit outside the adult ISA system in three important ways: they have their own annual limit, they kept the one-account-per-type restriction that adult ISAs lost in April 2024, and the money cannot be withdrawn until the child turns 18.
Quick Answer (Read This First)
- The annual subscription limit is £9,000 per child, across both Junior ISA types combined. It sits entirely outside the adult £20,000 allowance.
- A child can hold one cash Junior ISA and one stocks and shares Junior ISA at a time — and only one of each. That restriction was not removed by the April 2024 reforms.
- A Junior ISA is opened by someone with parental responsibility, who is the registered contact. A 16 or 17-year-old can open a cash Junior ISA for themselves.
- Anyone can pay in — grandparents, family friends — up to the shared £9,000 limit.
- No withdrawals before 18, other than in narrow circumstances such as terminal illness or death.
- At 16 the child can take over managing the account. At 18 it becomes an adult ISA.
The £9,000 Allowance, and How It Is Shared
The limit is per child, per tax year, and it covers both account types together. A child with £9,000 in a cash Junior ISA has nothing left for a stocks and shares Junior ISA that year.
Unused allowance cannot be carried into the following year — the same rule that applies to adult ISA allowances.
Contributions are gifts to the child and cannot be taken back. That is not a provider policy; it follows from the money being the child's property.
The parental settlement rule does not apply
Ordinary children's savings accounts carry a trap: where a parent gifts money to a child and the interest exceeds £100 a year, that interest is taxed as the parent's income.
Junior ISAs are outside this rule. A parent can fund a Junior ISA to the full £9,000 and the interest or growth remains the child's and tax-free. For any parent saving meaningful sums, this is the main structural advantage over a standard children's account.
Who Opens It, and Who Controls It
The account is opened by a person with parental responsibility, who becomes the registered contact — the only person who can change the account, switch provider or alter investments. Anybody may contribute, but nobody else gains control by paying in.
At 16, the child can become the registered contact and manage the account themselves. They still cannot withdraw.
At 18, the account matures into an adult ISA and the money becomes theirs to do as they wish. That is worth planning for rather than discovering: a sum built over eighteen years becomes fully accessible on a birthday.
Since 6 April 2024, the minimum age for opening an adult cash ISA has been 18, so 16 and 17-year-olds now use the Junior ISA route rather than holding both.
What Happens If the Rules Are Broken
Two Junior ISAs of the same type. A child may hold only one cash and one stocks and shares Junior ISA at a time. Where a second of the same type is opened by mistake — usually because a grandparent opens one without knowing another exists — the position is repaired rather than penalised. The provider or HMRC voids the invalid account, and the subscriptions are removed. Tax may be due on any interest or growth attributed to the voided subscriptions.
Going over £9,000. Providers are required not to accept subscriptions above the limit, but errors happen across two providers who cannot see each other's accounts. Excess subscriptions are void, removed in date order, and any interest or growth on them loses its tax-free treatment. There is no penalty charge in the way there is on a Lifetime ISA withdrawal — the money is repaired out of the wrapper, not confiscated.
Do not try to fix it yourself. Withdrawing money from a Junior ISA to correct an over-subscription is not possible in any case, and closing an account does not undo the subscription record. Contact the provider, which has a defined repair process with HMRC — the same architecture described in our guide on paying into two cash ISAs by mistake.
Child Trust Funds and Transfers
A child cannot hold a Child Trust Fund and a Junior ISA at the same time. Where a CTF exists, it must be transferred into a Junior ISA to move across — and transferring is often worthwhile, since CTF rates and charges have generally lagged the Junior ISA market.
Transfers are permitted between providers and between the two Junior ISA types. Where current-year subscriptions are transferred, the whole of that year's subscriptions must move together. As with adult ISAs, use the provider's transfer process rather than withdrawing, which for a Junior ISA is not an option anyway.
If a Child Trust Fund has already matured, our guide on accessing a matured Child Trust Fund at 18 covers what happens next.
Frequently Asked Questions
Looking for more on this topic? Browse all our savings guides.
Sources and Further Reading
This guide draws on the following legislation and official sources:
- Individual Savings Account Regulations 1998
- GOV.UK — Junior Individual Savings Accounts
- GOV.UK — Individual Savings Accounts
- HM Revenue & Customs
Free, impartial money guidance is available from MoneyHelper, the government-backed service run by the Money and Pensions Service.
Related: Accidentally Paid Into Two Cash ISAs | ISA Allowance Explained | All savings guides.
