OneFamily Junior ISA

A Junior ISA is a tax-free savings account for a child under 18, opened by a parent or guardian to build up money for their future¹. OneFamily is one of the providers that runs them, and it is the firm behind the Post Office's ISA range: Post Office ISAs are provided by OneFamily, and the Post Office only offers a stocks and shares Junior ISA².

That matters for anyone searching for a OneFamily Junior ISA, because the account you find may be badged as a Post Office product. Either way, the rules are the same. The child owns the money, it is a gift that cannot be taken back, and it stays locked away until the child turns 18³. OneFamily's own site carries today's charges and fund details, and those figures change, so check there before deciding anything.

This page covers what the account is, who can open one, how the charges work, how to apply or move an existing Junior ISA across, what protects the money, and what to do if something goes wrong.

What a OneFamily Junior ISA is and who it is for

A Junior ISA is a long-term tax-free savings account that can be opened by a parent or legal guardian to invest in their child's future¹. It is designed for children and young adults under the age of 18 to build up savings³, and it is a tax-advantaged savings product available to children under the ISA rules⁵.

OneFamily's Junior ISA is a stocks and shares account rather than a cash one. That means the money is invested, so its value can fall as well as rise, and it is a longer-term home for money than a cash account would be. The Post Office, whose ISAs OneFamily provides, only offers a stocks and shares Junior ISA².

The account suits anyone saving over a long horizon for a child: a parent putting aside a monthly amount, a grandparent making a one-off gift, or a family pooling contributions. It is not a place for money the child will need soon, because nothing can be taken out before 18.

A child can hold one cash Junior ISA and one stocks and shares Junior ISA at the same time, so a OneFamily stocks and shares account can sit alongside a cash Junior ISA held elsewhere². A single subscription, or several smaller amounts, can go to a cash account, a stocks and shares account, or any proportion between them, for the same named child³.

How it works

The child is the beneficial owner of everything in the account. Under the ISA rules, an account is a junior ISA account at any time when it is held by a child, and the child is the beneficial owner of the account investments³. The legislation sets out who counts as a child and an eligible child for these purposes⁵.

That ownership has a practical consequence: money paid in is a gift. An account manager must inform subscribers, other than the named child, that the subscription is a gift to the child⁴. It cannot be handed back, and the person who paid it in has no claim on it.

Only one Junior ISA of each type can be held at a time. A child under 18 can only have one Junior ISA, and where both types are used, that means one cash and one stocks and shares account². The annual Junior ISA subscription limit is set by the Government for each tax year, and providers publish it in their key documents⁶.

Contributions can come from anywhere once the account is open. Anyone can contribute, and other relatives and family friends can pay in too⁸. The only constraint is the annual allowance, which is shared across the child's Junior ISAs.

At 18 the account stops being a Junior ISA. The young person becomes eligible for an adult ISA at that point, and the money is theirs to control⁹. OneFamily contacts the person who looks after the Junior ISA about a month before this happens¹⁰.

How the fees and charges work

OneFamily charges an annual management charge on its Junior ISA, and fund charges apply on top. The exact percentages and any minimums are set out on OneFamily's own charges pages, and they change, so the provider's site has today's figures. What follows is how charges of this kind are structured across the market, so you can read a charges page with some idea of what you are looking at.

Platform or account charges are usually a percentage of the money invested, taken from the account rather than billed separately. True Potential's Junior ISA, for example, carries an ongoing platform fee, and adviser ongoing servicing fees on ISAs and Junior ISAs can run up to 1.5% per year¹¹.

Dealing charges apply when investments are bought or sold. Some providers bundle Junior ISAs into a paid plan: interactive investor's Junior ISA is free to add on its Plus and Premium plans, and Core plan customers can upgrade to open one¹², with the Plus plan giving free Junior ISAs for all your children¹³. Others charge nothing at all on junior accounts: Fidelity does not charge service fees on its junior accounts¹⁴.

Two features are worth knowing about. First, some providers waive their annual charge until the child turns 18, so the cost steps up when the account converts to an adult ISA¹¹.

Who can apply and how to apply

A Junior ISA application may only be made by a person over 16 who has parental responsibility for the eligible child, or by the eligible child themselves⁴. In practice that means a parent or guardian opens the account for a younger child, and a 16 or 17 year old can open one in their own name.

Providers apply that rule in slightly different ways. Bestinvest says only parents or a guardian with parental responsibility can open a Junior ISA, and that the parent or guardian should be 18 or older and UK resident⁸. Penrith Building Society offers its account to UK residents aged 0 to 16, with a person with parental responsibility applying where the child is under 16, and either the child or that person opening it at 16 or over¹⁶. Swansea Building Society requires the applicant to be 16 or more and to be the child, a natural parent, an adopter, someone granted parental responsibility by a court, or a local authority with parental responsibility¹⁷.

A 16 or 17 year old resident in the UK, or a UK Crown servant, or married to or in a civil partnership with a UK Crown servant, can open a Junior ISA for themselves⁶. Children are only eligible for an adult ISA when they turn 18⁹.

How you apply depends on the provider. Some are online only: NS&I accepts Junior ISA applications and management online at nsandi.com only⁶, and Fidelity's Junior ISA is opened online only¹⁸. Bestinvest says it can take less than 10 minutes to open a Junior ISA online, with money added by debit card and a transfer request started at sign up or later¹⁹. Others are branch or postal: Chorley Building Society requires an application in branch or by post with a completed form, at least £1 deposit, and proof of identity, address and residency²⁰, and the Hanley's Junior ISA is a branch-only account²¹.

To move an existing Junior ISA to OneFamily, ask OneFamily to start the transfer. Junior ISAs can be transferred between providers at any time at no charge, and the money keeps its tax-free status². Bestinvest's process is typical: open the new account online, complete a Junior ISA transfer letter of authority form, and return it by email or post¹⁹.

How your money is protected

OneFamily is authorised and regulated by the Financial Conduct Authority⁷. The firm behind it, Family Assurance Friendly Society Limited, holds firm reference number 110067 and has been authorised since 1 December 2001⁷. It also appears on the Bank of England's list of UK insurers authorised to carry out contracts of insurance²². OneFamily is a trading name of Family Equity Plan Limited, company number 2208249⁷.

Eligible deposits and investments are covered by the Financial Services Compensation Scheme. Moneybox states that its Junior ISA is protected by the FSCS²³, and cash Junior ISA providers state the same for their accounts. The FSCS limit applies per person, per firm, so money held in other accounts with the same firm counts towards the same limit.

There is a difference between cash and investments here. A cash Junior ISA is protected as a deposit, and that protection does not apply in the same way to a stocks and shares Junior ISA¹⁵. With an invested account, the FSCS covers the firm failing, not the investments falling in value. If markets fall, the money in the account falls with them, and no compensation is payable for that.

The ISA rules themselves add a layer of protection. An account manager intending to manage a junior ISA account must undertake to publicise the minimum amount that may be subscribed on a single occasion and the permitted means of payment, and to inform subscribers that the subscription is a gift to the child⁴. That is a regulatory duty, not a courtesy.

Problems, complaints and getting help

If something goes wrong with a Junior ISA, the first step is the provider's own complaints process. Family Building Society, for example, directs questions about account terms and conditions to its New Business Team on 03330 140141 or by email. OneFamily publishes its own contact details and complaints route.

If the provider does not resolve the complaint to your satisfaction, the Financial Ombudsman Service can look at it. The ombudsman publishes quarterly complaints data by product, which shows how many complaints reach it in each category. In the first quarter of 2026/27 it recorded 2,103 complaints opened about personal loans²⁴, and in the first quarter of 2025/26 it recorded 391 complaints about cash ISAs, including cash lifetime ISAs and help to buy ISAs²⁵. Those figures give a sense of the volume of complaints that escalate, not of any particular firm's record.

Free, impartial help is available. The Consumer Council offers guidance on savings accounts for consumers¹, and MoneyHelper provides free information on ISAs and savings. For debt problems, debt advice charities offer free help.

One timing point catches people out. When a Junior ISA is about to convert at 18, the provider contacts the person who looks after the account about a month before this happens¹⁰. If that contact is missed, the account still converts, and the young person takes control of it.