September 28, 2026Published by Tax Team2 on September 28, 2026Categories Income Tax Business TaxNew to Self Assessment? Register by 5 October 2026 if you need to report income for 2025/26New to Self Assessment? If you need to report income for 2025/26, find out who must register, the 5 October 2026 deadline, what records you need, and the key filing and payment dates.