Junior ISA or Junior SIPP: which long-term savings account for a child

A Junior ISA and a Junior SIPP are both long-term savings accounts for a child, and the choice between them comes down to three things: how much can go in, when the child can use the money, and what the tax system adds along the way.

A Junior ISA takes up to £9,000 per child per tax year, and the child can take the money out when they turn 18¹. A Junior SIPP takes up to £2,880 a year, which the government tops up to £3,600 with basic-rate tax relief, but the money cannot normally be touched until age 55, rising to 57 from 2028³. So the Junior ISA is bigger and more flexible; the Junior SIPP is smaller but gets an immediate government boost and is designed for retirement, decades away.

Both are tax-free while the money is invested. Neither is a savings account in the ordinary sense: a Junior ISA can be cash or stocks and shares, and a Junior SIPP is always invested. Around 1.6 million Junior ISA accounts were subscribed to in 2024 to 2025, with £2.5 billion paid in, so they are a mainstream choice rather than a niche one².

Junior ISA or Junior SIPP: the main differences

The two accounts are built for different jobs. A Junior ISA is a savings or investment wrapper that belongs to the child, with a £9,000 annual allowance and access at 18¹. A Junior SIPP is a pension, with a much smaller annual limit but tax relief added on top, and access tied to the pension age⁴.

A Junior ISA comes in two types: cash and stocks and shares, and a child can have one of each¹⁰. NS&I's Junior ISA, for example, is a cash ISA, and NS&I does not offer a stocks and shares Junior ISA⁸. A Junior SIPP is always invested, because it is a pension, and the money stays invested until the child reaches pension age.

The practical difference is what the money is for. A Junior ISA pot is available at 18, which suits a first car, university costs, a house deposit or simply a start in adult life. A Junior SIPP pot is not available at 18 at all, and is intended to compound for forty years or more. The tax relief is the reward for locking the money away that long.

There is also a difference in how the accounts are treated for tax on the way out. A Junior ISA has no tax to pay when the money is accessed, and no tax relief on the way in⁴. A Junior SIPP gets relief on the way in but is taxed as pension income when the child eventually draws it, under whatever rules apply then.

Allowances: £9,000 a year into a Junior ISA, £2,880 into a Junior SIPP

The Junior ISA allowance is £9,000 per child, per tax year¹. It resets each year on 6 April, and it is separate from the parents' or guardians' own ISA allowances, so paying into a child's Junior ISA does not use up any of the adult £20,000 allowance¹¹. Each child has their own allowance, so a family with three children can put £9,000 into each one in the same tax year.

The Junior SIPP allowance works differently. Up to £2,880 can be paid in each year, and the government adds £720 of basic-rate tax relief at 20%, taking the total to £3,600⁴. That £3,600 is the annual maximum including the government's top-up, not on top of it. Over 18 years, assuming the limits stay the same, that is a maximum of £162,000 paid into a Junior ISA, of which £12,960 would be tax relief in a Junior SIPP³.

The gap between the two allowances is the single biggest difference for anyone deciding where to put money. A Junior ISA can absorb far more each year, but it gets no government bonus. A Junior SIPP gets an immediate 20% boost on everything paid in, but the ceiling is low.

Junior SIPP tax relief turns £2,880 into £3,600

The tax relief on a Junior SIPP is the feature that makes it worth considering at all. A child who is not earning still gets basic-rate relief at 20% on contributions, so every £2,880 paid in becomes £3,600 once the government adds its £720⁶. That £720 is added on top of the money actually paid, every year, up to the £2,880 annual contribution limit.

The relief is added automatically by the provider, who claims it from HMRC. There is no need for the child to have any earnings, and no need to fill in a tax return. The £3,600 total is the annual maximum, so once the government's £720 is included, no more can go in that tax year⁴.

Over a childhood, the effect compounds. If the full £2,880 is paid in every year for 18 years, £12,960 of the total comes from government tax relief alone³. That money then stays invested, and any growth on it is sheltered from tax, because a pension is a tax-advantaged wrapper in the same way an ISA is.

It is worth being clear about what the relief is not. It is not a bonus that can be taken back out at 18. It is locked into the pension until the child reaches pension age, and when the money is eventually drawn it is taxed as income, under the rules in force at that time. The relief is a boost on the way in, not a gift on the way out.

When the money can be touched: 18 for a Junior ISA, 55 or later for a Junior SIPP

A Junior ISA cannot be touched until the child turns 18⁷. There are no withdrawals before then, with exceptions if the child dies or has a terminal illness⁸. When the child turns 18, the account automatically becomes an adult ISA and they can take out any money in it⁷.

A Junior SIPP is locked away far longer. Money in a SIPP or Junior SIPP cannot normally be accessed until age 55, rising to 57 from 2028³. That is a gap of nearly four decades between the two accounts, and it is the reason the Junior SIPP gets tax relief and the Junior ISA does not.

The access age is not fixed forever. The rise to 57 from 2028 shows that pension access ages can move, and further changes are possible before a child born today reaches retirement. Anyone paying into a Junior SIPP is accepting that the rules at the point of access may differ from the rules now.

For a parent weighing the two, the question is whether the money is meant to help the child at 18 or to give them a head start on retirement. A Junior ISA answers the first; a Junior SIPP answers the second. Some families use both, putting the bulk into a Junior ISA and a smaller amount into a Junior SIPP to capture the relief.

Who opens, manages and pays into each account

Both accounts have to be opened by an adult. A Junior ISA can only be opened and managed by the child's parent or guardian, and a grandparent cannot open one unless they are the child's legal guardian¹⁵. A Junior SIPP must be opened by a parent or legal guardian, who also manages the account until the child takes it over⁴.

Once the account exists, anyone can pay in. Grandparents, other relatives and family friends can all contribute to a Junior ISA or a Junior SIPP, even though they cannot open it. The money belongs to the child, not to whoever paid it in, and it cannot be taken back.

The person who runs the account is called the registered contact. For a Junior ISA, the registered contact is the only person who can change the account, for example from cash to stocks and shares, change the provider, or report a change of circumstances such as a new address⁷. A parent or guardian manages the account while the child is under 16, and from 16 the child can manage it themselves⁸.

There is a legal point behind the age 16 rule. A contract entered into by a child aged 16 or over is treated as if the child had been 18 or over when the contract was made, which is what allows a 16 or 17 year old to open and run a Junior ISA in their own name¹⁶. The same rule does not apply to a Junior SIPP, which stays under adult control until the child is 18.

What happens at 16 and 18

At 16, the child can become the registered contact for their Junior ISA and manage it themselves⁷. They can also open a cash Junior ISA in their own name, and they can open an adult cash ISA, because adult cash ISAs are available to children from the age of 16¹⁴. A 16 or 17 year old can apply to open a stocks and shares Junior ISA too, because the ISA rules allow the management agreement to have effect as though the child were 18¹⁹.

At 18, the Junior ISA automatically turns into an adult ISA⁷. The money is then the child's to use as they wish, and there is nothing the parent can do to stop them taking it out. This is the moment that catches some families out: a pot built up over 18 years becomes entirely the young adult's to spend, and the parent's intentions for it carry no legal weight.

A Junior SIPP does not change hands at 18 in the same way. Control passes when the child reaches 18, but they cannot withdraw from it until 55, or 57 from 2028³. So the child gains the ability to manage the investments, but not to spend the money.

For a Junior ISA, the provider usually writes to the registered contact about a month before the 18th birthday to explain what happens next⁸. Some providers automatically move the money into one of their adult accounts unless told otherwise, so it is worth checking the terms before the birthday arrives.

Tax when the money comes out

A Junior ISA is tax-free at every stage. There is no tax relief on contributions, but the money is sheltered from tax as it grows, and there is no tax to pay when it is accessed⁴. Interest on a Junior cash ISA is paid without UK Income Tax, and investments held in a stocks and shares Junior ISA do not attract dividend tax or capital gains tax²⁰.

There is also a specific rule that stops a child's savings being taxed as the parent's income. JISA income is excluded from the settlements legislation, so any income from a Junior ISA is not treated as the parents' income for tax purposes²². Without that rule, money given by a parent to a child could be taxed back on the parent.

A Junior SIPP is different. Contributions get tax relief on the way in, but the money is taxed as pension income when it is eventually drawn, under the rules in force at that time⁴. The tax-free lump sum rules that apply to pensions may also apply, but the amount and the terms depend on the rules when the child reaches pension age, which is decades away.

One further point on inheritance. If a child dies before 18, the money in a Junior ISA is paid to whoever inherits their estate, and the tax-free ISA inheritance rules do not apply⁹. If the child was over 16 and married, which is possible in Scotland and Northern Ireland, the money goes to their spouse and the ISA inheritance rules stand⁹.

Where the money is protected

Junior ISA cash held with a bank or building society is covered by the Financial Services Compensation Scheme, which protects deposits per person, per firm²³. Because the money in a Junior ISA belongs to the child, it counts against the child's own limit, not the parent's, so a child with a large Junior ISA at one firm could exceed the limit. If the money is held in a child trust fund or Junior ISA account and compensation is due, it has to be paid into another ISA rather than cashed²⁴.

A Junior SIPP is an investment, not a deposit, so it is not covered by the deposit protection scheme in the same way. Investments can fall as well as rise, and the value of a Junior SIPP is not guaranteed. If a provider fails, the compensation position depends on what went wrong and which scheme applies, and it is worth checking the provider's own documentation.

If a Junior ISA holder lacks mental capacity, the process for taking control of the account differs by nation. In England and Wales, an application has to be made to the Court of Protection for a financial deputyship order; in Scotland, applications go to the Office of the Public Guardian in Scotland; in Northern Ireland, they go to the Office of Care and Protection⁷.

For free, impartial help with any of this, MoneyHelper offers guidance on savings and pensions, and the Financial Ombudsman Service can look at complaints about a provider that has not been resolved. A debt advice charity can help if money is tight and the question is whether to keep paying in.