Sidekick Cash ISA Review3.23% AER (Sep 2026)

Cash ISA from Sidekick

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Protection

FSCS

Up to £120,000

Min balance

£1

Max balance

£20,000

Access

Instant

Interest paid

Monthly

Transfers in

Accepted

Bonus Terms

Bonus on new deposits for the first 6 months, on up to £20,000. After that the base rate applies.

Who Is This For

Learn more about Sidekick

New and existing savers
Those wanting easy access
Savers happy with a £20,000 cap

Additional Info

Savings are split across three partner banks, each FSCS-protected up to £120,000 — up to £360,000 in total.

Please verify all details with the provider – for more info read our Disclaimer

Estimated returns with Sidekick's Cash ISA

Want to know how much interest you will receive with Sidekick's Cash ISA?

Estimated interest

£1,000 saved

£32.30

At 3.23% AER

£5,000 saved

£161

At 3.23% AER

£10,000 saved

£323

At 3.23% AER

£20,000 saved

£646

At 3.23% AER

Estimated over one year, assuming the rate stays the same and interest stays in the account. Amounts outside this account's minimum or maximum balance are left out.

Our Expert Opinion on Sidekick Cash ISA

The 3.23% rate here is a bonus rate that only applies to new deposits for the first six months, on up to £20,000, after which it drops to whatever the base rate is at the time, and Sidekick does not publish that base rate upfront, so you need to be prepared to move your money once the honeymoon period ends. That said, it accepts transfers in and starts from just £1, which makes it accessible for most people looking to use or top up their ISA allowance. If you want a straightforward rate without a bonus structure to track, the Tembo Standard Cash ISA or XTB Cash ISA are both sitting at 4.00% in the alternatives worth comparing.
Jan Watermann (Co-Founder)DepositScout