Self Assessment Tax Return Deadline: What You Need to Know

As the Self Assessment tax return deadline approaches, many individuals across Northern Ireland are feeling the pressure. Whether you’re a sole trader, freelancer, landlord, or company director, meeting HMRC’s deadline is non-negotiable.

At LC Accountancy, we help make tax season a lot less stressful. Based in Ballymena, we work with clients throughout Northern Ireland, making sure they submit accurate, on-time returns while avoiding penalties.

Let’s break down what you need to know—and how we can help.


When is the Self Assessment Tax Return Deadline?

The key date to remember is:

🗓️ 31 January (midnight) — This is the deadline for:

  • Submitting your online Self Assessment tax return
  • Paying any tax owed for the previous tax year
  • Making your first ‘payment on account’ (if applicable)

If you miss this deadline, HMRC will usually issue an automatic £100 fine, even if you don’t owe any tax. The longer you delay, the more penalties and interest you could face.

Need help meeting the deadline? Contact LC Accountancy today — we’ll handle the process for you.


Who Needs to File a Self Assessment Tax Return?

You’ll need to file if you fall into any of the following categories:

  • Self-employed as a sole trader
  • A partner in a business partnership
  • A landlord earning rental income
  • You earn income from investments, dividends, or overseas sources
  • You have untaxed income from other sources
  • You’re a company director and paid via dividends

Not sure if you need to file? LC Accountancy offers straightforward advice, so you’re never left guessing.


Avoiding Late Filing Penalties

HMRC is very strict when it comes to deadlines. If your return is even one day late, you’re looking at an initial £100 penalty. After 3 months, additional daily fines apply, and further charges can be added after 6 and 12 months.

What’s more, if your payment is late, interest starts accruing immediately.

Save yourself the headache—LC Accountancy will ensure your return is filed correctly and on time, giving you peace of mind and more time to focus on your business.


We’re Not Just for January

While most people only think about tax returns in the run-up to the deadline, working with us year-round has big advantages. We’ll help you:

  • Stay organised with cloud bookkeeping
  • Forecast tax bills to avoid nasty surprises
  • Claim all available deductions and reliefs
  • Navigate changing HMRC rules
  • Plan effectively for your business or personal finances

We serve clients across Northern Ireland, offering expert, friendly support from someone who understands the local business landscape.

🌍 Learn more about our region: Northern Ireland on Wikipedia


How LC Accountancy Can Help

We handle HMRC for you
From registration to submission, we deal with the admin so you don’t have to.

We make tax simple
We’ll explain everything clearly, calculate your bill, and submit your return accurately.

We save you time
You run your business. Let us handle the numbers.

We’re local
Based in Ballymena, we proudly serve individuals and businesses throughout Northern Ireland.


Get Started Today

If the 31 January Self Assessment tax return deadline is looming and you still haven’t filed, don’t panic—but don’t delay either.

Let LC Accountancy take the stress out of tax season. Whether you’ve never filed before, are running behind, or just want the job done right, we’re here to help.

👉 Visit LC Accountancy Services to book an appointment or request a callback.