For parents, grandparents and guardians looking to save for a child’s future, a Junior ISA (Individual Savings Account) can be a tax-efficient and flexible way to invest. But the rules can seem confusing, especially with changes to the allowance each tax year. This guide breaks down the key Junior ISA rules for 2025 in simple terms, we shall cover contributions, transfers and how the annual allowance works.

What is a Junior ISA?

A Junior ISA (JISA), from the Children’s ISA,  is a long-term, tax-free savings account for children under the age of 18 who live in the UK. There are two types: a cash Junior ISA and a stocks and shares Junior ISA. A child can have one of each at the same time, and both can be used to save or invest on their behalf until they turn 18.

Importantly, a Junior ISA belongs to the child, which is true of both a Cash and an Investment ISA. While parents or guardians manage the account until the child turns 16, only the child can access the money when they reach 18. It’s important to note that here at the Children’s ISA, we only offer an Investment ISA but offer an array of different funds to suit your individual goals and investment profile. 

What is the 2025 Junior ISA allowance?

For the 2025/26 tax year, the Junior ISA allowance is £9,000. This is the maximum amount that can be paid into a child’s Junior ISA account in a single tax year (from 6 April 2025 to 5 April 2026).

The allowance is shared across both types of Junior ISA. So if a child has both a cash and a stocks and shares JISA, the combined total contributed to both accounts must not exceed £9,000 in the tax year.

Who can contribute to a Junior ISA?

Anyone can contribute to a child’s Junior ISA – parents, grandparents, friends or other family members. Crucially, however, only a parent or legal guardian can open the account. Contributions can be made regularly or as one-off payments, and as long as the total doesn’t go over the annual allowance, there’s no tax to pay on the interest or investment gains (most children are exempt from income tax anyway).

This makes a Junior ISA a popular birthday or Christmas gift choice for relatives who want to give money that grows with the child.

What happens when the child turns 18?

When the child reaches 18, their Junior ISA automatically becomes an adult ISA. At that point, the child takes full control of the account and can withdraw the money or continue saving. At that point, they can also open new ISA’s of their own.

Can you transfer a Junior ISA?

Yes, Junior ISA can be transferred between providers. For example, if you’re not happy with your current interest rate or investment options, you can move the account to a new provider without losing the tax-free status.

Transfers can be made:

• From one cash JISA to another
• From one stocks and shares JISA to another
• Between cash and Investment JISAs (in either direction)

Transfers must be made in full, and only one active account of each type is allowed per child at any time. Always check with the new provider before starting the transfer, and never withdraw the funds to move them – this would lose the ISA status and the tax implications this would entail.

Final thoughts

A Junior ISA is a smart, long-term savings option for children, with generous tax advantages and a clear set of rules. The £9,000 allowance for 2025/26 provides a great opportunity for families to build a strong financial foundation for the child’s future, whether through cash savings or investments.

This guide is intended for the 2025/26 tax year, as tax allowances are often updated each year, we would suggest referring to the latest government guidance to ensure you’re working with up-to-date figures. Saving early, even with small regular contributions, can make a big difference by the time the child turns 18.