Paying into registered pension schemes

Hi - I made a contribution payment into a SIPP in September 2023 towards unused allowance in the 2021-22 tax year. When completing my 2022-23 tax return, can I claim this contribution, or can I only do so when I complete my 2023-24 tax return?

Hi
You can only claim tax relief for pension payment in the tax year in which they were made.  
You would need to claim tax relief in your 23/24 tax return for payments made in September 2023.