Turning 18 and ISA allowance

Raefortoday

My son is turning 18 next month and has used his Junior ISA allowance for 25/26. When he is 18 does he get the full adult allowance of 20k for the remainder of 25/26 or does he need to wait for the 26/27 tax year to invest?

FrugaiMacDugal

This is from a search,

AI Overview

Yes, a 17-year-old can open a Junior ISA (JISA) and, since April 6, 2024, can also open a separate adult cash ISA

. This means they can have both accounts simultaneously, with each having its own separate annual allowance. However, they cannot open an adult Stocks and Shares ISA until they are 18. 

Junior ISA (JISA)

• A 16 or 17-year-old can open and manage their own JISA.
• For the 2025/26 tax year, the JISA allowance is £9,000.
• Money in a JISA is locked away until the child turns 18. 

• 
  

Adult ISA

• Cash ISA: A 16 or 17-year-old can open a cash ISA, and contributions are separate from the JISA allowance. For the 2025/26 tax year, the adult ISA allowance is £20,000.
• Stocks and Shares ISA: They cannot open an adult Stocks and Shares ISA until they are 18. 

• 
  

Important considerations

• Management: On their 18th birthday, the Junior ISA automatically transfers into an adult ISA, and the child can then manage it themselves.
• Total allowance: The JISA allowance and the adult ISA allowance are separate. A 17-year-old can contribute the maximum to both a JISA and a cash ISA in the same tax year, provided they meet the criteria for both.
• Transfer: You cannot transfer an adult ISA into a Junior ISA, though you can withdraw money from your own adult ISA and put it into your child's JISA. 

• 
  

DavidT67

Or in far less words than above,  YES, they get both JISA and ISA allowance in the tax year they turn eighteen.

singhini

That was my understanding aswell.

Its £9,000 until they are 18

And becomes £20,000 post their 18th birthday.

i think the existing JISA gets converted to an ISA   (how the JISA is converted depends on the individual banks own process [i think?]

Any contributions once the child is now 18 must use the adult ISA rules i.e. he will need to complete an adult ISA application (provide his NI number, confirm his home address etc.....) and cannot put any money into a JISA

jimjames

singhini said:

Its £9,000 until they are 18

And becomes £20,000 post their 18th birthday

So a total of £29,000 in the year they turn 18

singhini

jimjames said:

singhini said:

Its £9,000 until they are 18

And becomes £20,000 post their 18th birthday

So a total of £29,000 in the year they turn 18

No 
Total of £20,000
£9,000 allowance becomes £20,000

I did once [by mistake] put £25,000 into ISA's within the same year and nothing was ever said to me (it was £10k in one ISA and then £15k into another ISA later that year. It was also before we were allowed to put money into more than one ISA and nothing was ever said to me). Ive moved the money over the years and nothing doing.

I'm not advocating others do this [i'm just thinking to myself......... all that paperwork gets sent around and around and no one seemingly looks at it............. bonkers!]

Raefortoday

So looks like a difference in interpreting the rules. 9k allowance can be topped up to 20k in the year he turns 18 ( so 11k can be paid into an adult ISA) OR both 9k and 20k allowance ( 20k can be paid into an adult isa!

refluxer

FrugaiMacDugal said:

This is from a search,

AI Overview

Adult ISA

• Cash ISA: A 16 or 17-year-old can open a cash ISA, and contributions are separate from the JISA allowance. For the 2025/26 tax year, the adult ISA allowance is £20,000.

This isn't correct and is a good example why it's always a good idea to go direct to a trustworthy source rather than relying solely on AI.

The minimum age to open an adult ISA was actually changed from 16 to 18 when ISA rules changed back in April 2024.

There is a small exception though for a specific age group. From https://www.gov.uk/individual-savings-accounts

"If you were born between 6 April 2006 and 5 April 2008, you can open one cash ISA before you turn 18"

Ch1ll1Phlakes

I believe this link gives the correct information and I've attached a screenshot from the link for what I think is the relevant part. Junior Individual Savings Accounts (JISAs) for managers: setting up Junior ISAs - GOV.UK


Note: these rules are from a 2016 article. Adult Cash ISAs can no longer be opened by anyone under the age of 18 but these rules still apply (in part). In bullet point 2 add from their 18th birthday, ... and that should be up to date rules.

@refluxer mentions this above with the exact restriction "If you were born between 6 April 2006 and 5 April 2008, you can open one cash ISA before you turn 18" however all of these people are now older than 18.

EDIT: I've removed the out of date information from my following post.