With the UK tax year ending on 5 April, many individuals and business owners start asking the same question: When do I actually need to file my tax return for the tax year ending 5th April 2026? While the deadlines may seem far away, understanding them early—and preparing in advance—can save significant time, stress, and potentially money. Key Self Assessment Deadlines (2026 Tax Year) For the 2025/26 tax year (ending 5 April 2026), the main deadlines are: • 31 October 2026 –

The deadline for submitting your UK self-assessment tax return depends on how you file it: • Paper return: 31st October following the end of the tax year (e.g., for the 2023/24 tax year, the deadline is 31st October 2024). • Online return: 31st January following the end of the tax year (e.g., for the 2023/24 tax year, the deadline is 31st January 2025). You must also pay any tax you owe by 31st January. If you make advance payments (Payments on Account), the second instalment