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A cash Isa is a really important part of your personal finances, as otherwise you could lose a big chunk of your interest to tax.

In this regularly updated round-up, This is Money picks our five favourite cash Isas for savers from all those currently on the market.

It is essential reading to help you choose a top savings account for new cash isa money and transfers – and we detail the top easy access and fixed rate cash Isa deals.

This top Isa round-up has been keeping our readers updated on the best savings deals since 2014 and is kept up-to-date weekly. Bookmark it for the very latest developments.

> Check all the top cash Isa rates in our savings tables

How an Isa works and why you should have one

Each year in April, savers are given a fresh Isa allowance that qualifies for tax–free interest.

For the 2026/27 financial year, starting 6 April 2026 and ending 5 April 2027, the limit is £20,000. From April 2027, the limit for cash Isas will fall to £12,000 for under 65s.

You can transfer Isa money between a stocks and shares Isa and a cash Isa savings account and vice-versa. But again the rules change from April 2027, at which point stocks to cash transfers will be barred.

Cash Isa rates have been rising, along with non-tax free rates. It is worth opening one to shield money away from the taxman, especially with rates moving upwards.

You can also transfer an old Isa for better returns. If you have a sizeable pot, this can often be more lucrative than tracking down the best rate for new money. Here's a quick guide to Isa saving.

It is possible to switch your current year's cash Isa if you move the entire amount, but it is far simpler to get your choice right in the first place.

Get an Isa to beat savings tax 

Higher rates have dragged more people into the savings tax net, meaning a cash Isa's shelter is even more valuable. 

An Isa is worth having, despite the tax-free savings interest allowance of £1,000 a year for basic rate taxpayers and £500 for higher rate taxpayers. 

If you're a basic-rate taxpayer earning 5 per cent interest, having more than £20,000 in savings will tip you into tax, for a higher-rate taxpayer that figure is £10,000 and if you are in the 45p tax bracket, you get no savings allowance at all.

You may also want to look into a stocks and shares Isa. Read about how to choose the best stocks and share Isa.

Our five favourite Isas:

Trading 212, easy–access, 4.51%*

 – Facts: £1 to open

– Transfers in: Yes (bonus rate only applies to this tax year's contributions)

– Flexible: Yes

> Full details at Trading 212* 

This is Money says: Trading 212 has consistently offered one of our favourite cash Isas because it usually sits near the top of our rate table, it accepts transfers and has a low minimum deposit. 

The rate includes a 0.91 per cent bonus rate which lasts for 12 months for new customers, after which it falls to 3.6 per cent. Use this special This is Money Trading 212* link to secure it.

Existing customers can earn 3.6 per cent with interest paid monthly. 

The Isa is competitive because it has a good underlying rate, no withdrawal limits and is flexible.

Trading 212 will also apply the boosted rate to contributions made this tax year when transferring an Isa from another provider – previous tax year contributions receive the lower rate.

The account can only be opened by downloading Trading 212's app. There are no limits to how many times you can withdraw your money and Trading 212 will not reduce your interest rate for accessing your money.

Trading 212's Isa is a flexible Isa which is a big benefit to savers with the financial fire power to max out their Isa limit each year. 

Any cash deposited with the Trading 212 cash Isa is fully FSCS protected, as are all of the accounts in this list. Funds in the Trading 212 Isa are held in partner bank accounts with Barclays, NatWest and JPMorgan, so they're FSCS protected with these providers.

Customers are able to see the percentage of their cash held at each bank is in the interest on the cash tab in the Trading 212 app.

It means if you already have money in Barclays, NatWest or JPMorgan, you'll need to be careful not to breach the £120,000 limit if you put money away with Trading 212.

Read our Trading 212 review to find out how it performs as an investment platform. 

Plum, easy-access, 4.44%* 

 – Facts: £1 to open

– Transfers in: Yes (transfers receive lower 4% rate)

– Flexible: Yes

> Full details at Plum* 

This is Money says: The savings and banking app Plum returns to this list with the second-best easy-access Isa by rate, plus it's now flexible meaning you can withdraw money and replace it in the same tax year without affecting your allowance.

The bonus rate is 1.90 per cent, making the underlying rate 2.54 per cent, which is rather low. It's worth shopping around for a different rate after the year is up. 

Your money is FSCS protected up to £120,000, as are all accounts in this list.

Coventry BS, one-year fix, 4.60%

– Facts: £1 to open

– Transfers in: Yes

– Flexible: No

> Full details at Coventry BS

This is Money says: If you prefer to save with well-known names, Coventry BS is currently offering the top one-year fixed rate Isa. There's a low minimum deposit to get started and transfers are accepted.

Coventry BS is the UK's second-largest building society and last year purchased the Co-Operative Bank. 

Hodge Bank, two-year fix, 4.66%

– Facts: £1,000 to open

– Transfers in: No

– Flexible: No

> Full details at Lloyds Bank

This is Money says: Hodge Bank is offering the top rate on a two-year fixed Isa, but beware that you can't transfer in from other providers.

Hodge Bank is based in Wales and was established in 1987. 

If you'd like to transfer an Isa into a two-year fix, have a look at Aldermore Bank which pays a slightly lower 4.65 per cent. 

The best cash lifetime Isa

Moneybox, Cash lifetime Isa, 4.45%

– Facts: £1 to open

– Transfers in: Yes (not partial transfers)

– Flexible: No

> Full details at Moneybox

This is Money says: For those aged between 18–39 who are either saving up to buy their first home or towards retirement, Moneybox has consistently offered a top rate on its lifetime Isa.

Save up to £4,000 each tax year and get a 25 per cent government bonus. The deal is only available through its app. 

The rate includes a 1.65 per cent fixed bonus for the first year, making the underlying rate 2.8 per cent.