Check how to register for Self Assessment
You must tell聽HM Revenue and Customs (HMRC)聽by 5 October 2025 if you need to complete a tax return for the previous tax year and you have not sent one before.
The previous tax year started on 6 April 2024 and ended on 5 April 2025.
You can tell HMRC by registering for Self Assessment.
If you tell HMRC after 5 October 2025, you could get a penalty.
This service is also available聽in Welsh (Cymraeg).
If you鈥檝e registered before
If you鈥檝e registered for Self Assessment before but did not send a tax return last year, you must register again to reactivate your account.
If you鈥檙e waiting for a Unique Taxpayer Reference (UTR), you can check when you can expect a reply from HMRC.
Before you start
You should check if you need to send a tax return before registering.