Check how to register for Self Assessment
Register if you're a partner or partnership
You’ll need to complete form SA401 to register for Self Assessment and Class 2 National Insurance.
If you need to register your partnership
Register if you’re a partner or partnership
You’ll need to register for both:
- Self Assessment
- Class 2 National Insurance
To register, you’ll need to complete form SA401.
If you need to register your partnership
You must also register your partnership if you’re the ‘nominated partner’.
There are different ways to register:
- for limited liability partnerships
- if you’re a partner that’s not an individual, for example a company or a trust
When to register
You must tell HM Revenue and Customs (HMRC) by 5 October if you need to send a tax return and you have either:
- not sent a tax return before
- registered before but did not need to send a tax return for the tax year 2024 to 2025
You could be fined if you do not.
If you register after 5 October 2026, HMRC will send you a letter confirming when you need to send your tax return by. This will be 31 January 2027 or 3 months from the date on the letter, whichever is later.
Your answers
- 1. Why do you need to send a Self Assessment tax return?
- You're a partner in a business partnership
- Change 1. Why do you need to send a Self Assessment tax return?