Best 1 Year Fixed Rate Cash ISAs in October 2026

Shawbrook's 1 Year Fixed Rate Plus Cash ISA pays 4.97%, which sits above the cash ISA market average but 0.28% behind the category leader at 5.25%. The £10,000 minimum makes it one for savers with a decent lump sum, and at 1.87% above August 2026 CPI of 3.1%, your money does grow in real terms.

The main catch is the early exit penalty: withdrawals or transfers out before maturity cost 90 days' interest, taken from capital if needed, so only commit money you can lock away for a year.

Investec's one-year Fixed Rate Cash ISA pays 4.95%, which sits above the cash ISA market average but 0.30% behind the category leader at 5.25%, so it is solid without being the best available. At 1.85% above August 2026 CPI of 3.1%, your money does at least grow in real terms.

The minimum is £1,000 and transfers in are accepted, making it a reasonable home for existing ISA money.

The main catch is that access is locked until maturity, and early closure costs 90 days' interest deducted from your balance.

Castle Trust Bank's 1 Year Fixed Rate e-Cash ISA pays 4.95%, which sits above the cash ISA market average but 0.30% behind the category leader at 5.25%, so it is decent without being the best available. It does beat inflation by 1.85% against CPI of 3.1% (Aug 2026), which is the real job of a cash ISA.

The minimum is £1,000 and the account accepts ISA transfers in, making it a reasonable home for existing ISA money. The firm catch is that your money is locked until maturity, with charges if you withdraw early, so only commit funds you will not need for the year.