Reporting overseas income and when to pay tax

I returned from living in the US earlier this year, and had no tax liability to the UK for the tax year 2023-2024. I am now a UK resident, and will owe UK taxes for the 2024-2025 tax year. I have retired, and my income consists entirely of interest and dividends (no pension yet), almost all of which is from US based investments. This income will exceed the personal allowance and the savings and dividends allowance. As no UK tax is withheld at source, do I have to make any tax payments before I prepare my 2024-2025 tax return in 2025 or 2026? Is there any income or predicted amount of tax due where I would have to pay taxes early or inform HMRC of my income? If so, how and when do I need to do this? Or can I just leave doing anything until the end of the 2024-2025 tax year? Thank you.

Hi,
Please refer to:
Tax on foreign income
Thank you.

I had already read through that section, and from my reading of it, I need to register for self -assessment so I can report my income, but not until "5 October following the tax year [I] had the income." As this is income for the current (2024-2025) tax year, this suggests I don't need to register - or pay any tax - until 5 October 2025. However that means - as I have no UK sourced income that is PAYE or has tax withheld - that I don't pay any UK tax at all on income received April 2024-April 2025 during that tax year, and then will have a large tax bill due when I eventually file (after October 2025). This seems like something HMRC wouldn't want! Could you please confirm that is the case: i.e. that assuming my only income in the tax year 2024-2025 is foreign savings interest and foreign dividends, regardless of the amount, that my first requirement to tell HMRC about the income or pay taxes is October 2025? Thank you.

I am a resident and live in UK. I am retired and have no income from work. My living is merely based on the interest earned from overseas and UK. Does the tax on interest earned from overseas and from UK carry the same treatment? Thanks.

Hi,
Please see the link below.
Tax on foreign income: Reporting your foreign income
Thank you.

Hi Cascat.
The 5 October is the deadline in which to register for Self Assessment to ensure you are not issued with any penalties for failing to notify HMRC that a return is required. For income received in the 2023 to 2024 tax year, you have until 31 October 2025 to file the return and pay any tax due.
Thank you.

The first return I will need is for the 2024-2025 year, but I will shift those dates along a year! Thanks for the reply.