What happens at 18

If the named individual doesn’t access a Junior ISA by the time they turn 18, the funds in the account will not be forfeited. It stays exactly where it is. The fund will still be invested and fully owned by the young person, but it will be inaccessible until they verify their identity with the provider. 

A JISA automatically becomes a standard adult ISA on the named individual’s 18th birthday. There is no form filling needed for this aspect of the switch from JISA to a standard adult ISA. From the age of 16, a child can become a ‘registered contact’ (or named individual) and can manage the account but still cannot access the funds within the account. 

So what happens from a parent’s perspective? A parent or guardian has a hard cut-off when a child becomes 18. They have no right to access the account; the funds within the account 100% belong to the child. Typically, a Junior ISA provider (like here at the Children’s ISA) will write to the young person before or near their 18th birthday and ask for ID verification so that they can unlock the account and take control. 

What happens if the fund is not accessed 

The money still sits there and is 100% owned by the named individual. The money is not lost or returned to the parent or the guardian of the child who is named on the account. It is worth bearing in mind that if a provider loses contact entirely with both the registered contact and the child, there is no simple standard legal process that exists. The UK’s Dormant Assets Scheme uses a six-year “gone away” test. In practice, this means a provider could eventually pass the money to an authorised reclaim fund after six years of trying to make contact, but it stays legally the child’s and can still be reclaimed at any time. It isn’t publicly documented whether providers apply this to matured, unclaimed Junior ISAs specifically, but the principle holds either way – the money in a Junior never gets forfeited and/or given away.

Child Trust Funds are the bigger story 

Child Trust Funds (CTF’s) were created in the mid 2000’s. Every child was given £250 at birth by the government to encourage the habit of saving and investing. CTF’s were abolished in 2011, and Junior ISA’s were created in their place (minus the government incentive). Staggeringly, according to the government’s own data, there are 750,000+ CTF’s unclaimed as of April 2026. Why? The reasons are manifold. Some parents didn’t realise the account was opened for their child, providers may have lost touch over the past 16+ years, or funds could have been moved between accounts without a child being cognisant of the fact that this money even existed. Incredibly, the total amount unclaimed is estimated to be between £1.5-£1.6 bn, which averages around £2,200 per child. 

HMRC started writing letters to 21-year-olds in the spring of 2026, which named their provider and included a scam warning. HMRC will never send people a text, call or email so if anyone receives contact from someone purporting to be from HMRC should be reported to them immediately. 

There is a “Find a Child Trust Fund” tool on the government gateway website. A CTF, when located, can be transferred to a Junior ISA if the child is under 18 or an adult ISA if they are an adult. 

How to stop a Junior ISA becoming dormant 

To proactively stop a Junior ISA becoming dormant, there are several steps that can be taken, and many of these steps can fall under the umbrella of good financial hygiene. 

Change of address: If the named individual (the parent or guardian) has changed their address, the provider needs to be informed. Many dormant account issues start with a returned letter and not an account that has been lost. 

Tell the provider if the child has moved: If a child has turned 18 and is now in charge of the ISA, the provider should be informed. 

Talk to the child: A child can become a manager of the account from their 16th birthday. Parents or guardians could also consider engaging with their child about the fact that the Junior ISA exists and how much money is held within the account. For many children, the maturity letter could be the first time they have heard about it. 

FAQ’s

What happens to a Junior ISA at 18 if it’s not accessed?

On the child’s 18th birthday, a Junior ISA automatically becomes a standard adult ISA, whether or not the young person does anything about it. If they don’t verify their identity or log in, the money simply stays where it is, fully theirs and still tax-free. They just won’t be able to withdraw it or manage it online until they complete the provider’s verification steps.

Can a parent still access a Junior ISA after the child turns 18?

No. Once the account matures, the parent or guardian’s access ends completely, even if they were the registered contact right up until that point. From then on, only the young person can manage or withdraw from the account, other than in cases of death or terminal illness.

Is money ever lost if a Junior ISA or Child Trust Fund is never claimed?

No, the money isn’t lost or forfeited, and there’s no time limit on claiming it. 

How do I find out if I have a Child Trust Fund?

Use the free “Find a Child Trust Fund” tool on GOV.UK. Sign in with a Government Gateway ID or GOV.UK One Login and provide your name, address, date of birth and National Insurance number, and HMRC will reply within around three weeks with the name of the provider holding the account. There’s no need to use a paid tracing firm; HMRC’s own service does the same thing for free.

Can I transfer an old Child Trust Fund into a Junior ISA?

Yes. If the child is still under 18, a Child Trust Fund can be transferred into a Junior ISA. Once they turn 18, it can instead be moved into an adult ISA.