Hi,
If you do not need to complete a Self Assessment tax return, all you would need to do is submit a P85 here:
Get your Income Tax right if you're leaving the UK (P85)
If you do have to complete a 2023 to 2024 Self Assessment tax return, then you complete it as normal. There is no need for SA109, as it is not relevant to 2023 to 2024. Instead, please provide information in the free hand box, detailing the date you left the UK and any forwarding address.
If you will have no UK income in the coming tax years, while not resident in the UK, then tax returns are no longer required. You can contact our Self Assesment team to confirm you have left the UK and tax returns are no longer required.
Self Assessment: general enquiries
Thank you.