When can I file my 2025/26 self assessment tax return?

You can file your 2025/26 tax return from 6 April 2026. The tax year runs from 6 April 2025 to 5 April 2026, and HMRC opens their systems as soon as the tax year finishes.

What are the deadlines for the 2025/26 tax return?

For paper returns, the deadline is 31 October 2026. For online returns, the deadline is 31 January 2027. The deadline to pay your tax bill is also 31 January 2027.

Why is it a good idea to file my tax return early?

Filing early gives you more time to save for your bill, ensures faster refunds if you overpaid, helps you avoid busy HMRC phone lines, and prevents the automatic £100 fine for late filing.

How should I prepare for my 2025/26 tax return?

Keep all your business receipts, invoices, bank statements, and P60/P45 forms safe and organized. Alternatively, you can hire a professional accountant to manage your records and file the return for you.

When can I file my 25-26 self assessment

Wojciech

Diploma in Professional Accounting
Diploma for Financial Advisers
HMRC Authorised Tax Agent

You can file your 2025/26 tax return from 6 April 2026.

The 2025/26 tax year runs from 6 April 2025 to 5 April 2026. As soon as the tax year finishes, HM Revenue and Customs (HMRC) opens their systems so you can submit your details right away.

Important Deadlines to Remember

While you can start filing in early April, you do have a few months to actually get it done. Here are the absolute final deadlines for the 2025/26 tax year:

Paper returns: If you prefer to send paper forms by post, HMRC must receive them by 31 October 2026.
Online returns: If you file online (which most people do), you have until 31 January 2027.
Paying your tax bill: The deadline to actually pay the tax you owe is also 31 January 2027.

Why It Is a Good Idea to File Early

Even though you have until January 2027 to hit the online deadline, getting your return out of the way as soon as possible after 6 April 2026 is highly recommended. Here is why:

You get time to save: Filing your return doesn’t mean you have to pay the bill right then. If you file in April, you will know exactly how much you owe, giving you over nine months to save up before the payment deadline in January.
You get refunds faster: If it turns out you have paid too much tax during the year, filing early means HMRC will send your refund to you much sooner.
You avoid the panic: The HMRC phone lines get incredibly busy in December and January. If you file early and need to call them for help, you won’t be stuck on hold for hours.
You won’t get fined: Missing the January deadline results in an automatic £100 fine, even if you don’t owe any tax. Doing it early removes this risk completely.

How to Prepare Now

To make filing a breeze when April 2026 rolls around, the best thing you can do right now is keep good records. Keep all your business receipts, invoices, bank statements, and any P60 or P45 forms safe and organized in one place.

Alternatively, having a good accountant can take the entire job off your hands. A professional can manage your records, make sure you are claiming all the right expenses, and file the return for you, giving you total peace of mind and freeing up your time to focus on your work.

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