WhichBrokerThe rate, without the marketing
Trading 212’s Cash ISA pays 3.60% AER, variable, calculated daily and paid monthly. It tracks the Bank of England base rate minus 0.15 percentage points, so when the Bank moves, this rate moves with it on a lag, not instantly. New customers who apply through a qualifying promotional route can get 4.75% AER for 12 months, which is the standard rate plus a temporary 1.15-point bonus. After 12 months, or immediately for anyone who did not qualify for the promo, the account reverts to the plain tracker rate.
That structure is standard for the market: a promotional rate front-loads new customers, then the account settles into ordinary competition on the tracker. Diarise the date your bonus period ends and check the tracker rate against the rest of the market when it does; loyalty rarely pays in cash ISAs.
Why it is protected differently from the rest of the platform
This is the detail most reviews skip, and it is the reason we cover the Cash ISA separately from interest on uninvested cash in the Invest account. Trading 212 confirmed directly that Cash ISA funds are held exclusively in banks — never split into qualifying money-market funds the way interest-bearing balances in the Invest and CFD accounts are. The practical effect: the entire Cash ISA balance sits under FSCS deposit protection, up to £120,000 per person per banking group since the December 2025 rise from £85,000. There is no QMMF portion to fall outside that cover, which is the qualification we had to make about interest on cash everywhere else on the platform.
What “flexible” actually buys you
The account is a flexible ISA. Withdraw £5,000 in November and redeposit it in February, and provided both happen in the same tax year, none of it counts against your £20,000 annual allowance a second time. Without flexibility, that redeposit would need spare allowance and might not fit.
The catch is timing, not the rule itself: flexibility resets every 6 April. Withdraw £5,000 on 4 April and try to redeposit it on 10 April and you have crossed into a new tax year, so the redeposit now uses that year’s fresh allowance rather than restoring the old one. For anyone moving money in and out of a cash ISA around the tax year boundary, the date matters more than the mechanism.
Fitting it around the rest of your allowance
The full UK ISA allowance for 2026/27 is £20,000, shared across every ISA type you hold — cash, stocks and shares, innovative finance, lifetime. Put £8,000 into a Trading 212 Cash ISA and you have £12,000 left for a Stocks and Shares ISA, in any provider, in any split you choose. From 6 April 2027 the cash portion for under-65s narrows to £12,000 of that £20,000 total, with the full allowance preserved for money going into stocks and shares or for anyone 65 and over; that change does not affect the 2026/27 tax year this guide is written for, but it is worth knowing before committing a large lump sum to cash for years ahead.
Moving money in
New money goes in like any deposit: bank transfer, card or digital wallet, subject to the same funding rules as the rest of the account (card and wallet deposits are fee-free up to a lifetime €2,000 threshold, covered in Trading 212 fees explained). Transferring an existing ISA in is different and should never be a simple withdrawal-and-redeposit: use Trading 212’s ISA transfer process, which moves the funds directly between providers and preserves the tax-free wrapper without touching your allowance. Trading 212 accepts transfers from both an existing Cash ISA and a Stocks and Shares ISA, and you can also move money between your own Trading 212 Cash ISA and Stocks and Shares ISA. One firm condition: the promotional bonus rate applies only to new money from newly eligible customers, not to transferred-in balances, so do not transfer in expecting the 4.75% headline.
Where it does, and does not, fit
For an emergency fund or short-term cash sitting inside the tax-free wrapper, a variable-rate tracker with full FSCS deposit cover and no platform fee is a reasonable, low-drama choice, and the flexible-ISA rule means it can absorb withdrawals without wasting allowance. What it is not is a substitute for investing: 3.60% before the promo, or even 4.75% during it, is a savings return, and money with a multi-year horizon has historically done better in the Stocks and Shares ISA on the same account, accepting the volatility that comes with it. If you already hold cash outside an ISA and have unused allowance, moving it in front-loads a tax-free rate that fully taxable savings accounts cannot match at the higher tiers of income tax. If you are chasing the single highest rate in the market regardless of provider, check the whole-of-market tables before committing, since promotional rates elsewhere sometimes beat this one for a comparable term.
Verdict
A straightforward, fully protected, flexible cash ISA bolted onto the account you may already use for investing, at a rate that tracks the base rate rather than trying to beat it. The promo is worth taking if you qualify and plan to hold cash for a year anyway; the underlying tracker is competitive but not exceptional once the bonus drops away. For the full account picture, including how this sits alongside the Invest account and CFDs, see the Trading 212 review.
Preguntas frecuentes
What is the Trading 212 Cash ISA rate?
3.60% AER variable as standard, tracking the Bank of England base rate minus 0.15 percentage points, so it moves when the base rate does. New customers applying through a qualifying promotional link can get 4.75% AER for the first 12 months, made up of the standard rate plus a 1.15-point bonus that then drops away.
Is the Trading 212 Cash ISA covered by the FSCS?
Yes, in full, as a deposit. Cash ISA balances are held exclusively in banks, never in the qualifying money-market funds used for interest on uninvested cash elsewhere on the platform, so the whole balance carries FSCS deposit protection up to £120,000 per person, per banking group.
Is the Trading 212 Cash ISA flexible?
Yes. You can withdraw money during the tax year and pay it back in without losing that portion of your £20,000 annual allowance, as long as the repayment happens in the same tax year as the withdrawal. Most easy-access cash ISAs work this way, but it is worth confirming for any account before you rely on it.
Can I transfer an existing ISA into Trading 212?
Yes, both from another Cash ISA and from a Stocks and Shares ISA, using the provider's ISA transfer process rather than withdrawing and redepositing, which would use up allowance and could break continuity of tax-free status. The promotional bonus rate does not apply to transferred-in balances, only to new money from eligible new customers.
