2024/25 UK Tax Return Season Is Open

With the 2024/25 tax year having concluded on 5th April, the season for filing a self assessment tax return is now underway. For many freelancers living in the UK, the task of preparing a tax return UK can feel like another complex item on an already long to-do list.

And if you are in the unique position of managing financial affairs across two countries (for example, having a rental property overseas, or overseas investment income), the process of completing a UK tax return can feel more complicated than it needs to be. To cap it off, the free HMRC personal filing service does not allow for declaring foreign income, so a lot of taxpayers need to either pay for separate software, or get a firm like No Worries Accounting to complete their tax return (which of course we encourage you to do 😊)

This year, getting your self assessment tax filing right is more important than ever because it’s the final tax year under the old non-dom rules. This guide is designed to help. We will walk you through the essential deadlines for getting your tax returns filed, explain why this year is a landmark period for anyone with foreign income, and provide clarity on the UK self-assessment tax return process. Our goal is to help you navigate your obligations and file a self assessment with confidence.

First Things First: Do You Need to File a Self Assessment?

Before we dive into the details of deadlines and non-dom rule changes, it is important to confirm whether you actually need to be filing a self assessment tax return. The UK’s Self Assessment system is primarily for individuals who have income that has not been fully taxed at source through an employer’s PAYE (Pay As You Earn) scheme. For many of our clients, financial circumstances often extend beyond a single UK salary.

You are generally required to complete a tax return if any of the following common situations applied to you during the tax year (6th April 2024 to 5th April 2025):

1. You are a director of a limited company. Even if you pay yourself entirely through PAYE, being a company director often triggers the need to file.
2. You earn income from self-employment. If you work as a sole trader or freelancer, you must complete a self-employed tax return to declare your profits.
3. You receive rental income. This includes income from a property here in the UK or, as is common, from a rental property you still own back in Australia or New Zealand.
4. You have significant foreign income or capital gains to declare. This is a frequent trigger for expats, covering everything from interest on overseas bank accounts to gains made from selling shares.

If any of these sound familiar, then managing your self assessment and tax return obligations is a necessity. The next step is to ensure you are fully aware of the key dates involved.

Mark Your Calendar: Unmissable Tax Deadlines

When it comes to your tax assessment UK, missing a deadline is a guaranteed way to receive a penalty notice from HMRC. It is super useful to have these dates firmly in your calendar to ensure your tax returns filed on time. The HMRC are not shy when it comes to issuing penalties, especially these days where they are in revenue maximisation mode.

1. 5th October 2025: This is the deadline to register for Self Assessment. If this is your first time filing a self assessment tax return, you must inform HMRC by this date to let them know you need to file.
2. 31st October 2025: The deadline for submitting a paper tax return. We generally advise against this route as the online system is more efficient and gives you a more generous deadline.
3. 31st January 2026: This is the main deadline for most people. It is the final date to submit your online tax return and, to pay the tax you owe from the 2024/25 tax year.

Leaving it to the last minute is a recipe for stress. Getting your self assessment return organised early means you have sufficient time to gather your documents and address any complexities without the pressure of an impending deadline. Plus if you have any tax to pay, its not a mad scramble to gather some funds together.

A Landmark Year: The Final Return Under Current Non-Dom Rules

This is where the 2024/25 tax year becomes particularly significant. The tax return you file for this period is the final one that will operate under the current non-domicile rules, making this a landmark year for any non-doms with overseas income.

For years, many non-domiciled residents have used the “remittance basis” of taxation. In simple terms, this allowed you to pay UK tax on your foreign income and gains only if you brought, or “remitted,” them into the UK. This system, which has been a cornerstone of tax planning for expats, is being completely abolished from 6th April 2025.

There are two main groups of clients that would use the remittance basis as a tool for tax planning. (1) The Higher Earners. Claiming the remittance basis means you lose your personal allowance in the UK. If you earn over £125,140 you have no personal allowance anyway, making the remittance basis a no-brainer in a lot of cases. (2) Big Foreign Earners. If you have some chunky offshore earnings, potentially taxed at a low rate, then losing your personal allowance can be better than declaring that foregn income in the UK.

The 2024/25 self assessment tax filing is therefore your last opportunity to file under this long-standing framework. It represents the end of an era, and is the last chance to report under these specific rules before the new, and in many ways less flexible, Foreign Income and Gains (FIG) regime takes over.

This makes proactive planning for the massive FIG 2025/26 changes more important than ever, and it all starts with getting this year’s HM revenue tax return self assessment right.

Common Pitfalls for Expats

Navigating the HMRC self assessment tax return can feel like a minefield when you have financial ties offshore. Over the years, we have seen a few common areas where people can get caught out, turning a straightforward process into a complicated one.

1. Declaring Worldwide Income
2. A common misconception we encounter is that if income is already taxed in Australia or New Zealand, it can be ignored on a UK tax return. This is incorrect. As a UK tax resident, you are typically taxed on your worldwide income. That rental profit from a flat in Sydney or the interest earned on an NZ bank account is part of your tax returns in the UK and must be declared.
3. Pensions and Investments
4. Another area that often causes confusion is the UK tax treatment of schemes like KiwiSaver or Australian Superannuation. These are not straightforward UK pensions, and how they are reported on your UK self-assessment tax return requires specialist knowledge to ensure compliance and avoid unexpected tax charges. Drawing down on your offshore pension while tax resident of the UK can have significant and unpleasant tax side effects. It especially hurts Kiwis and Australians.
5. Claiming Double Tax Relief
6. Thankfully you will not be taxed fully on the same income in both countries. Double Taxation Agreements exist to prevent this. However, relief is not automatic. You do not simply ignore the income; you must declare it on your return and then correctly claim a Foreign Tax Credit Relief for the tax already paid overseas. This process can be fiddly and is an easy place to make mistakes, potentially leading to you overpaying tax.

Conclusion: Take Control of Your Tax Return

The window for submitting your 2024/25 self assessment for tax is now open. The deadlines are firm and will approach faster than you think, and this year’s return carries extra weight. It marks a significant turning point as the last one to be filed under the familiar non-dom rules for foreign income.

We understand that navigating the UK tax system, especially with the international elements that Kiwis and Aussies face, can feel complex and burdensome. It is easy to put it off, but the peace of mind that comes from knowing your affairs are in order and you have met your obligations is invaluable.

Whether you need assistance to file a self assessment for the 2024/25 tax year, or you want to proactively plan for the significant tax changes ahead, our team is here to help. We specialise in helping Kiwis and Aussies in the UK manage these exact complexities. Get in touch with us today to ensure a smooth, stress-free tax season.