Instant Access Cash ISA
Dip in when you need. Earn tax-free while you do.
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Compare our cash ISAs
Want tax-free interest? Here’s how our Instant Access stacks up against our Fixed Rate options.
Helpful tip!
AER stands for Annual Equivalent Rate and illustrates what the interest rate would be if interest was paid and compounded each year. This allows you to compare easily what return you can expect from your savings over time. Tax-free means interest is exempt from UK Income Tax under current HMRC ISA rules. Tax treatment depends on individual circumstances and may change in the future.
Why choose a Cash ISA?
Our Instant Access Cash ISA gives you full flexibility and tax-free interest, perfect for everyday saving with no strings attached.
Put in up to £20,000 this tax year and move over any ISAs you’ve got elsewhere.
Withdraw whenever you like and top it back up without losing your allowance.
We add a little extra on top of your base rate, and it all remains tax free. It is already included in the rate you see advertised.
Name them after your goals and watch each one grow.
Earn interest daily, paid into your account monthly – always tax-free.
From opening to managing, it’s all sorted in our secure app.
Split, save, smash your goals
Got plans? Stick your savings in separate ISA accounts, name them, and watch them grow. Same tidy rate. Tax-free interest.
Know your ISA allowance
Each tax year, you can deposit up to £20,000 across all your ISAs. Our Cash ISAs are flexible, which means anything you withdraw can be replaced within the same tax year without affecting your allowance.
With our Instant Access ISA, you can make unlimited withdrawals and replacements whenever you need to.
Bring your ISA balance with you
Already have an ISA elsewhere? No problem. We make it easy to digitally transfer in your existing ISA savings, whether it’s from this tax year or previous years. You can also hold accounts with multiple providers at the same time.
Fund your Cash ISA in minutes
Make quick, secure payments from your linked bank account whenever you like, straight from the Tandem app. Powered by regulated Open Banking technology.
You're in safe hands
We’re a fully regulated UK bank so you can rest easy knowing that your money is protected, up to £85,000 by the Financial Services Compensation Scheme (FSCS), the UK’s deposit guarantee scheme.
That's enough from us, hear it from those who matter
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Got a question?
We’ve got answers! Explore our most common savings questions, or head to our full FAQ page to find more.
Part of your deposits help fund greener choices for others — like home energy upgrades, low emission vehicle, and solar panels. In 2024, Tandem customers helped save over 70,000 tonnes of CO₂, the equivalent of taking 15,000 petrol cars off the road for a year.
Yes. Tandem is a fully regulated UK bank. Your savings are protected up to £85,000 by the Financial Services Compensation Scheme (FSCS).
You’ll have a 14-day window to decide whether to reinvest, move into an Instant Access ISA, withdraw, or transfer to another provider. If we don’t hear from you, your funds move into a Matured Funds Cash ISA at a variable rate so they keep earning interest tax-free
Yes. You can hold up to 20 Tandem ISAs (Instant Access or Fixed Rate), so you can separate savings goals or take advantage of new rates.
Interest is calculated daily and paid monthly, tax-free.
Yes. Simply start the process with your new provider and they’ll contact us. Transfers normally process with 4-5 working days, but can sometimes take up to 15 working days. If you’re in a Fixed Rate ISA, an early withdrawal charge will apply.
Yes. You can transfer an ISA from another provider without it affecting your allowance. Just open a Tandem Cash ISA and start the transfer in the app.
Yes, both our Instant Access and Fixed Rate Cash ISAs are flexible. That means you can withdraw and replace money in the same tax year without eating into your allowance. For example, if you deposit £20,000 but withdraw £5,000, you can still replace that £5,000 within the same tax year without exceeding your £20,000 limit.
Instant Access: withdraw and replace freely.
Fixed Rate: you can withdraw, but an early withdrawal penalty applies.
No – all interest earned in your ISA is completely tax-free and doesn’t use up your allowance.
Yes. You can now subscribe to more than one ISA of the same type in the same tax year (since April 2024). Just make sure your combined contributions don’t go over the annual £20,000 limit.
You can save up to £20,000 each tax year across all your ISAs (not just with Tandem). The overall amount a customer can hold across their Cash ISAs is £250,000.
Instant Access Cash ISA – variable tax-free rate, dip into your savings anytime.
Fixed Rate Cash ISA – fixed rate, with funds locked in for a fixed term. Great for long-term saving with a guaranteed return.
Both are FSCS-protected up to £85,000.
A Cash ISA (Individual Savings Account) lets you earn interest without paying tax on it. For the 2024/25 tax year, which runs from 6 April 2024 to 5 April 2025, you can save up to £20,000 across all your ISAs, tax-free.
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