How Do You Open an ISA? Eligibility, Transfers and Rules

You open an ISA with a provider such as a bank, a building society or a stockbroker. gov.uk says you must be 18 or over, and either resident in the UK or a member of the armed forces or a Crown servant (or their spouse or civil partner) living abroad. In the 2026-27 tax year the overall allowance across all your ISAs is £20,000, and gov.uk says you can use it in one account or split it across several.

The site's rules data was last checked against gov.uk on 26 September 2026. Figures typed in this guide may not yet reflect a later change, and the descriptions of gov.uk pages are summaries that may also lag. The current figures are on the ISA rules at a glance page. General information only, not financial advice.

Who can open an ISA?

The GOV.UK page on who can open an ISA says you must be 18 or over to open an ISA. It adds that you must also be one of the following:

resident in the UK;
a member of the armed forces or a Crown servant (for example diplomatic or overseas Civil Service), or the spouse or civil partner of one, if you do not live in the UK.

The main GOV.UK guide to Individual Savings Accounts says the same, and also says you cannot hold an ISA with someone else. That page lists four types of ISA: cash, stocks and shares, innovative finance and Lifetime. The page on who can open an ISA sets out an extra age condition only for the Lifetime ISA, and does not list separate conditions for the other three types. The pages read do not say how residence is decided in a particular case, so that is a question for HMRC or the provider.

Who can open a Lifetime ISA?

The Lifetime ISA has an extra age condition. The GOV.UK page on who can open an ISA says that if you are opening a Lifetime ISA you must also be under 40, which means from 18 to 39 inclusive. The GOV.UK Lifetime ISA guide says you must make your first payment into the ISA before you are 40, and that you can pay in up to £4,000 each year until you are 50. It also says the £4,000 counts towards the overall annual ISA allowance. The Lifetime ISA guide says the account stays open after 50, but you can no longer pay in or earn the government bonus.

The guide pages read do not say how many Lifetime ISAs one person can hold in total. They do say, on the how ISAs work page, that you can only pay into one Lifetime ISA in a tax year. The rules for taking money out of a Lifetime ISA are different from other ISAs; see Lifetime ISA withdrawal charge: worked examples.

Who can open a Junior ISA?

A Junior ISA is opened for a child, not by the child. The GOV.UK Junior ISA guide says the child must be under 18 and living in the UK. It says a child living abroad can have one only if a parent is a Crown servant and the child depends on them for care. It says parents or guardians with parental responsibility can open and manage the account, and that the money belongs to the child.

The same page says the child can take control of the account at 16 but cannot withdraw the money until 18. It says your child can have one or both types of Junior ISA (cash and stocks and shares). The page does not state a maximum number of accounts. The annual limit for a Junior ISA is separate from the adult allowance and is shown on the ISA rules at a glance page.

What does a provider ask for?

The GOV.UK page on how to open an ISA says you can get an ISA from banks, building societies, credit unions, friendly societies, stock brokers, peer-to-peer lending services, crowdfunding companies and other financial institutions. It says you will need your National Insurance number, and that you can find it online if you do not know it.

That page does not list anything else a provider asks for. It says to contact the provider directly for more information about how to open an ISA with them. So proof of identity, proof of address, payment methods and any minimum deposit are questions for the provider; the pages read do not say.

How is an account opened, and when does the first payment count?

The pages read give the route but not the steps. The page on how to open an ISA names the kinds of firm that offer ISAs and points you to the provider for the process. It does not say when a first payment is counted as made, whether that is the date you pay, the date the provider receives the money or the date the account opens. The pages read do not say, so ask the provider.

What gov.uk does say is that the tax year runs from 6 April to 5 April, and that every tax year you can save up to £20,000 in one account or split the allowance across multiple accounts (how ISAs work). The pages read do not say how a payment made close to the tax year end is dated, so that is a question for the provider. For the Lifetime ISA, the first payment matters for another reason: it must come before you are 40.

Can you hold more than one ISA of the same type?

The how ISAs work page gives examples of the allowance being shared across types and across accounts. One example is two cash ISAs and a stocks and shares ISA paid into in the same tax year. The page says you can save up to £20,000 in one account or split the allowance across multiple accounts. For the Lifetime ISA it is stricter: you can only pay into one Lifetime ISA in a tax year.

So the older idea of one ISA of each type is not what the page describes for cash, stocks and shares or innovative finance ISAs. The page does not say whether every provider will accept payments into an account when you hold another of the same type elsewhere, so that is a question for each provider. For the wider picture of the types, see the guide to the different types of ISAs.

How is a transfer in different from a new payment?

A new payment is money you pay in from outside your ISAs, and it uses up part of the allowance. A transfer moves an existing ISA to another provider. The GOV.UK page on transferring your ISA says that to switch providers you contact the provider you want to move to and fill out an ISA transfer form. It says the investment can have been made this year or in previous years.

The same page says that if you withdraw money instead of transferring it, you will not be able to reinvest that part of your tax-free allowance again. It gives timescales: transfers between cash ISAs should take no more than 15 working days, and other transfers no more than 30 calendar days. For innovative finance ISA investments it says to ask your provider. It also says Lifetime ISAs and Junior ISAs have transfer limits, without listing them, and that other investments held in an innovative finance ISA may not be transferable.

The pages read do not say whether a transfer counts towards the annual allowance, so this guide does not state it. The how ISAs work page also says you cannot transfer non-ISA shares you already own into an ISA (with an exception for employee share schemes). Our guide to how an ISA transfer works goes into more detail.

What if someone is not eligible, or pays in too much?

The pages read do not say what happens if someone opens an ISA when they are not eligible, or pays in more than the allowance. The how ISAs work page does not cover paying in too much, and the Lifetime ISA guide does not say what happens if the £4,000 limit is exceeded. This guide therefore does not describe any consequence, and does not guess at one.

Gov.uk does say you can call the ISA Helpline if you have questions about the tax rules for ISAs. A provider can also say how it handles a payment that would go over a limit. The ISA calculator and the ISA rules at a glance page show the current limits for the 2026-27 tax year, and the learn page on allowances and rules explains them in plain words. For rule changes announced for later years, see upcoming ISA changes.

What to check

Which type of ISA is on offer: cash, stocks and shares, innovative finance or Lifetime?
What does the provider need to see to open the account, beyond a National Insurance number?
When is a payment counted as made for the tax year, and how is that recorded?
If moving an existing ISA, does the provider use its own transfer form, and how long does it say the move will take?
For a Lifetime ISA, when is the first payment due relative to the age condition?
For a Junior ISA, who will be the registered contact, and who has parental responsibility?
Where can the current rules be read? The main place is the GOV.UK ISA guide, and the site's ISA rules page summarises them.

Frequently asked questions

Do I need my National Insurance number to open an ISA?

The GOV.UK page on how to open an ISA says you will need your National Insurance number. It does not list other documents, so the provider is the place to ask about those.

Can I open an ISA jointly with someone else?

No. The GOV.UK guide to Individual Savings Accounts says you cannot hold an ISA with someone else. A Junior ISA is opened by a parent or guardian, but the money belongs to the child.

Can I pay into two cash ISAs in the same tax year?

The how ISAs work page gives an example of saving in one cash ISA and another cash ISA in the same tax year, within the overall allowance. It says that for Lifetime ISAs you can only pay into one in a tax year.

Can I open an ISA if I live outside the UK?

Only in the cases gov.uk names: if you are a member of the armed forces or a Crown servant, or the spouse or civil partner of one, while living outside the UK. A Junior ISA for a child abroad has its own narrow condition, set out above.

This guide does not constitute financial advice. Your personal situation, tax position, and savings goals may mean different strategies are appropriate. Consider speaking to a regulated financial adviser if you are uncertain.