Yes, you can diversify your investments across any combination of ISAs. For current year investments you can only invest in one of each type. Please make sure you do not exceed the maximum allowance of £20,000. For example, you could split your allowance across one Cash ISA, one Stocks and Shares ISA and one Innovative Finance ISA.

For previous year ISA investments you can have as many different ISAs as you would like. There is no limit other than the amount a particular ISA manager will allow you to transfer. For example you can have multiple Cash ISAs, Stocks and shares ISAs and Flexible ISAs, as well as a lifetime ISA if elligible.