What's the best way to claim ISA tax allowance before the tax year ends?

I've been maxing out my ISA allowance every year for a while now, and the key thing is to just get the money in before April 5th - that's when the tax year ends in the UK. You can pay in a lump sum if you've got the cash available, or set up regular payments throughout the year, whichever works for your situation. The main ISAs worth considering are Cash ISAs if you want something safe, Stocks and Shares ISAs if you're comfortable with market risk, or a mix of both since you get £20,000 combined across all types. Just make sure whatever you put in actually settles before that deadline, because transfers can sometimes take a few days to clear.

The deadline's actually April 5th for the tax year ending, so you've got a bit of time if we're talking about the current year. Just make sure whatever you're putting in goes into an actual ISA account before that date - the money needs to be in there, not just transferred. I did mess this up once by assuming a transfer would clear in time and it didn't, so now I just do it well in advance to be safe. As long as it's sitting in your ISA before April 5th, you're golden for that tax year's allowance.