Can a 16 or 17 year old open a cash ISA?

A 16 or 17 year old cannot open a new adult cash ISA today. The minimum age for opening one rose from 16 to 18 on 6 April 2024, and the rules that let 16 and 17 year olds open one anyway ended on 5 April 2026¹. Anyone who was 16 or 17 on 5 April 2024 kept the right to hold and pay into a single adult cash ISA until their 18th birthday, and that group is now the only one that can¹.

For everyone else under 18, the tax-free savings account is a Junior ISA, and a Junior Cash ISA is the cash version of it. A young person can open their own Junior Cash ISA from the age of 16, and a parent or guardian can open one for a child at any time⁵. The money is locked away until 18, when the account becomes an adult ISA⁷.

This page sets out who can open what, who can pay in, how transfers work, and what happens when the account holder turns 18.

New adult cash ISAs now start at 18

The change came in on 6 April 2024. The legislation substituted 18 for 16 as the age at which a person can apply to open an account that is not a Junior ISA or a Lifetime ISA¹. The government's own note on the regulations describes it as "increasing the age at which a cash ISA can be held from 16 to 18"¹. NS&I's product information states plainly that "the minimum age for opening a cash ISA has increased from 16 to 18"².

Providers have applied the new age across their cash ISA ranges.

The change applies to cash ISAs specifically. Stocks and shares ISAs were already only available from 18, and Legal & General's guidance confirms you have to be 18 or over to open one¹⁴. So the practical effect of the 2024 change was to bring the cash ISA into line with the stocks and shares ISA: from 6 April 2024, no one under 18 can open a new adult ISA of either kind.

The government's annual savings statistics note that adult cash ISAs were, before the change, "available to children from the age of 16", and that eligible children could hold both a Junior cash ISA and an adult cash ISA at the same time¹⁵. That overlap is what the 2024 rules ended for new savers.

Who kept the right to a cash ISA at 16 or 17

The change was not retrospective. The regulations kept the old age of 16 for one group: individuals who had reached 16 on or before 5 April 2024 and had not subsequently reached 18¹. The explanatory note to the regulations says the same, describing the exception for "individuals who are 16 or 17 years old on 5th April 2024 (and who have not subsequently reached the age of 18)"¹.

For that group, the right was to hold, apply for or transfer a single cash ISA account¹. The government's note on the regulations confirms that "investors aged 16 or 17 as at 6 April 2024 will still be able to" open an account³. Which? reported the change at the time as the minimum opening age for adult cash ISAs being raised from 16 to 18⁴.

Two limits matter:

• It is one cash ISA, not several. The exception covers a single account.
• It is temporary. The transitional arrangements ended on 5 April 2026, and they only ever applied to those who were 16 or 17 on 5 April 2024⁴. A young person who turned 16 after that date has no route to an adult cash ISA before 18.

Building societies set the position out for their own customers. Suffolk Building Society states that if you were aged 16 or 17 as of 5 April 2024, you can open and subscribe to one single adult Cash ISA until you are 18¹⁶. HSBC's guidance notes that some providers may allow you to open a Cash ISA if you are covered by the transitional arrangements, and that you need to be 16 or 17 years old as of 5 April 2024¹⁰.

What 16 and 17 year olds with an existing cash ISA can still do

If you are in the transitional group, the account you hold is a normal adult cash ISA in every respect except the age at which you opened it. You can keep paying into it, and you can transfer it to another provider.

Coventry Building Society tells customers that if they are 16 or 17 and already have an ISA with it, they can keep the account and continue to pay into it¹⁸. Nationwide says that 16 or 17 year olds with an existing Nationwide cash ISA can pay in, transfer or reinvest¹³. Suffolk Building Society's product terms say the same: a saver who was 16 or 17 as of 5 April 2024 can open and subscribe to one single adult Cash ISA until they are 18¹⁶.

On transfers, the ordinary ISA transfer rules apply. Nationwide's transfer guidance covers moving an ISA to another provider, and first direct's transfer pages set out how a Cash ISA transfer works¹³. The receiving provider has to accept the account, and the transfer is arranged between the two providers rather than by withdrawing the money and paying it back in.

The ISA rules on what a cash account can hold also apply. Legislation from 2008 provides that in the case of a cash account, the current year's subscriptions and the previous years' subscriptions may only be transferred in the ways the regulations allow¹⁹. In practice this means a cash ISA transfer goes to another cash ISA, or to a stocks and shares ISA where the rules permit it, and the money keeps its tax-free status throughout.

What a 16 or 17 year old in this group cannot do is open a second adult cash ISA. The exception is for a single account, and the ordinary rule that a saver may subscribe to only one cash account in a tax year still applies¹⁹.

A Junior ISA is the cash ISA option under 18

For anyone under 18 who is not covered by the transitional arrangements, the Junior ISA is the tax-free savings account. A Junior Cash ISA is the cash version, and a Junior ISA can also be held in stocks and shares.

The age rules are straightforward. A Junior cash ISA is for children under the age of 18²⁰. Legal & General's guidance states that a child aged 16 or over can open a cash junior ISA⁵. Skipton Building Society says parents or guardians can open a Junior Cash ISA for a young person at any time, and that a young person can open their own from 16⁶. TSB tells customers that if the child is between 16 and 17 they must open a junior ISA account in their own name²¹.

The account is always in the child's name and the money belongs to the child. A young person can only have one cash Junior ISA in their name at a time, and the annual Junior ISA investment limit is set by the government for each tax year²². The limit itself is published each year in the provider's summary box and on the provider's website²².

There is a difference between a Junior ISA and an adult cash ISA that matters for a 16 or 17 year old.

Opening a Junior Cash ISA yourself at 16 or 17

A young person aged 16 or 17 can open a Junior Cash ISA in their own name. The rules on who may apply are set out in legislation: a junior ISA application may be made by a person who is over 16 and who either has parental responsibility for the eligible child or is the eligible child²³.

Providers describe the same split.

• Nottingham Building Society says a Junior ISA can only be opened when the child the account is for is aged 17 or under, and that at 16 or 17 the child can open it themselves²⁵.
• Interactive Investor's guidance states that only parents and legal guardians can open Junior ISAs for children under 16, while children aged 16 and 17 can open a Junior ISA for themselves²⁶.
• The Progressive Building Society says a child can open their own account from age 16, or a parent or someone with parental responsibility can open one²⁷.
• NatWest sets out the same choice: the child's parent or legal guardian if they are under 16, or a 16 or 17 year old opening the account for themselves²⁸.

Building societies apply this in their account terms. Family Building Society states that children aged 16 or 17 may open and operate a Junior Cash ISA on their own behalf, as the account holder²⁹. Mansfield Building Society says that where the child is under 16 only a person with parental responsibility can apply, and that children aged 16 or 17 may open and operate a Junior Cash ISA on their own behalf³¹. Nottingham Building Society's savings guidance repeats the under 16 rule³³.

NS&I, which runs a cash Junior ISA, states that for children aged under 16 only their parent or legal guardian can open an account, and that children aged 16 or 17 can open their own³⁴. Once the child reaches 16, they can manage the account online after registering with a signed form³⁴. NS&I's Junior ISA is a cash ISA³⁵.

Switching from a Junior ISA to an adult ISA at 18

A Junior ISA does not stay a Junior ISA. The government's guidance states that Junior ISAs automatically turn into an adult ISA when the child turns 18⁷. Once the account holder reaches 18, the account becomes an adult ISA and they can access the money in it³⁶.

Some providers move the money into a named adult account rather than simply relabelling the Junior ISA. NS&I states that on the child's 18th birthday the Junior ISA ends and it will automatically transfer the money into an adult cash ISA provided by NS&I, with notice about a month before³⁴. NS&I's key document says the same: when the young person is 18, it will transfer the Junior ISA into an adult cash ISA from NS&I²². Its guidance for taking ownership of savings confirms that when you reach 18 it will automatically transfer the money from your Junior ISA into an adult cash ISA from NS&I³⁷.

Skipton Building Society describes the same outcome in general terms: a child can only access the money when they turn 18, and the money held in a Junior ISA then transfers to an Easy Access Cash ISA for adults⁶.

The practical point for a young person approaching 18 is that the money does not disappear and does not become taxable. It moves into an adult ISA, and from that point the ordinary adult ISA rules apply, including the annual allowance and the choice of moving the money to a different provider. A saver who wants the money somewhere else at 18 can transfer the adult ISA afterwards, using the normal ISA transfer process¹³.

Where the rules differ and what to check

The age rules are set in legislation and apply across the UK, so there is no difference between England, Scotland, Wales and Northern Ireland on when a cash ISA can be opened or when a Junior ISA becomes an adult ISA¹.

What does vary is provider practice. Not every provider offers a Junior Cash ISA, and not every provider that offers one lets a 16 or 17 year old open it online. Some require a signed application form, as NS&I does for a 16 or 17 year old registering to manage the account³⁴. Family Building Society's Junior Cash ISA application form is a paper form²⁹. A young person opening their own account should expect to provide identification and may need to post documents.

The other thing to check is the transfer position. A 16 or 17 year old with an adult cash ISA under the transitional arrangements can transfer it, but the receiving provider has to accept it, and the transfer must follow the ISA rules¹³. A Junior ISA can be moved to another Junior ISA provider, and the whole balance must move if the account is transferred out³⁸.

For anyone who wants to understand the wider picture, our guides to who can open an ISA and Junior ISAs explained set out the eligibility rules in more detail, and what happens to a Junior ISA at 18 covers the move into an adult account.