Tax resident in Portugal January 2023 - December 2023

Hi, I became a tax resident in Portugal in January this year and will be until December this year before returning to the UK. The tax year for Portugal is January - December. I will be paying tax on the full year in Portugal but I believe I will need to declare and pay tax in the UK for both 2022/2023 and 2023/2024 due to the crossover of tax years. Could someone please advise what forms I need to fill out or what sections on the standard self-assessment form I need to be aware of? Thanks, Gareth

HI
On the tax return, you will need to include HS304 -
Non-residents tax relief under double taxation agreements (Self Assessment helpsheet HS304)

Thank you! Can I do this online? I have two more questions, please: 1) Do I need to declare all income for the tax year 2022/2023 on the return, even the time I was a tax resident in Portugal? 2) The section "Date your books or accounts start". Would this be from April 5 2022 to the time I became a tax resident in Portugal (January 2023)?

Hi Gareth Hayes,
If you qualify for split year then you only report any foreign income for the UK part of the year:
RDRM12000 - Residence: The SRT: Split year treatment: Contents.
If you do not qualify then you will need to report all your foreign income to the UK:
Tax on foreign income
The guidance at RDRM12150 at www.gov.uk will help you work out if split year treatment applies.
If claiming this, you need to complete the SA109 residence page and therefore need to file on paper.
Thank you.