The Flagstone Cash ISA is provided in partnership with WealthKernel, an FCA-authorised firm which manages the ISA.
Our best Fixed Rate Cash ISAs
Spread your money across different terms, so you choose when each part becomes available
We update this table daily, so rates and banks may change. We’ve already deducted our share of the interest from these rates.
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Why open a Fixed Rate Cash ISA with Flagstone?
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Convenient
Open tax-free accounts with multiple banks in one ISA.
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Flexible
This is a flexible ISA, so you can withdraw as much as you like without affecting your allowance.
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Rewarding
Enjoy exclusive rates and strong returns.
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Practical
Transfer your existing ISAs to Flagstone for free, and stop the sprawl for good.
Fix with Flagstone for peace of mind
Managing multiple Cash ISAs has never been so simple.
Flagstone Cash ISA
Open as many tax-free accounts as you need with one ISA wrapper
Competitive rates, all available with one login
Reserve your next rate in advance
Traditional Cash ISAs
Different apps and platforms for each ISA
Lose time to ISA admin and comparing high street rates
No ability to reserve your rate in advance
How does a Cash ISA work with Flagstone?
Any money you pay into your ISA wrapper counts towards your
annual ISA allowance.
Use this to fund your ISA holding account.
Your nominated UK current account
Fund
Withdraw
ISA wrapper
This acts as a temporary home for your funds while you choose which tax-free accounts to open.
Your Flagstone ISA holding account
Deposit
Return
Deposit into as many accounts as you like from multiple banks. When your accounts mature, use the funds to open new accounts, or withdraw to your nominated account.
Earning interest
Tax-free account
Tax-free account
Tax-free account
Tax-free account
How Flagstone
makes money
For each account you open with our bank partners through Flagstone, we receive a small share of the interest. We deduct that share before we feature any account in our platform – so the rate you see will always be the rate you receive.
We don’t charge admin, management, or platform fees.
Build your ISA, your way
Manage multiple tax-free accounts in one platform, and move money effortlessly to secure better rates.
What is a Fixed Rate Cash ISA?
You agree to lock your cash for a set period – for example, one, two, or five years – in exchange for a predictable, competitive interest rate. Your interest rate is fixed for the whole term, but you may have to pay an early withdrawal penalty to access your money before the term ends.
The interest you earn is tax-free.
Can you withdraw money from a Fixed Rate Cash ISA?
In general, you can only withdraw money from the tax-free accounts in your Fixed Rate Cash ISA when the term ends.
You may have to pay an early withdrawal charge for accessing funds earlier.
How often is interest paid on the tax-free accounts in a Fixed Rate Cash ISA?
For Fixed Rate accounts, banks apply interest to your account either annually and at maturity, or at maturity only.
Maturity refers to the date when the term of your Fixed Rate account ends.
Interest is paid to you at maturity.
How will the 2027 ISA allowance changes affect my Fixed Rate Cash ISA?
Your annual Cash ISA contribution limit will reduce to £12,000 from 06 April 2027 for most savers. But if you’re aged 65 or over, you can continue to save £20,000 a year in Cash ISAs if you wish.
The change in the rules applies to future deposit limits. It will not affect Cash ISA savings you already hold.
What is the minimum deposit for a Fixed Rate Cash ISA?
The minimum deposit to join Flagstone is £10,000. Once you've been onboarded, you can open savings accounts in the platform as well as the Flagstone Cash ISA, which is where you can access tax-free Fixed Rate accounts.
Through our platform, you can then spread your funds across multiple banks and terms.
Savings accounts may have different minimum and maximum deposit requirements, which are specific to the accounts you choose to open.
Are my deposits FSCS protected in Fixed Rate Cash ISAs with Flagstone?
Yes. Provided your deposits are eligible, they're protected up to £120,000 per client, per banking group. This includes deposits made in Fixed Rate accounts within the Flagstone Cash ISA.
Evolve your savings style
Discover other ways to save with Flagstone.
Learn more about how ISAs work
We’re at your service
Still need answers? Whether you’ve opened your Flagstone account or you’re just getting started, we’re here to help.
Call us on +44 (0)203 745 8130, Monday-Friday 9am-5.30pm.






