ISA Transfers

You can transfer ISA subscriptions from one provider to another if they allow it.

If you didn't use up your full ISA allowance so far this tax year, you can add more to it, up to that allowance. If you withdraw money from it, you cannot replace it.

If you didn't use up your ISA allowances from previous tax years, you cannot credit more to them to make up for the unused allowances after that tax year has ended, but you can add more to them as part of this year's allowance, if your provider permits it.

You can open a new ISA with one provider in this tax year, and transfer previous years allowances to that or other providers, subject to that provider allowing transfers in.

In my view, the way to go is to first open a new ISA with this year's allowance.

Then -

If this new ISA allows transfers in, transfer the NatWest money to it.

Or

Open another ISA (with no money) that allows transfers in and transfer the money from the NatWest to that.

The reason for this is that the accounts with the best rates often do not allow transfers in so two accounts - one for your new money and one for your previous year's money - is often the better way to go.

Yes, the best way is to transfer all your existing ISAs from previous years into one account - the provider that offers the best rate while allowing transfers in, and then open a new completely separate ISA with the provider that offers the best rate for new ISA subscriptions.

You can't open two ISAs otherwise, as you can only add new money to one ISA per year.