HM Revenue and Customs (HMRC) must receive your tax return and any money you owe by the deadline they set each year. HMRC must receive your paper tax return by 11:59pm on 31 October 2025 or you’ll get a late filing penalty . When submitting an online tax return, you must press send by 11:59pm on 31 January 2026 or you’ll get a late filing penalty . If you miss this deadline, you’ll have to pay another way. If you register late, your filing deadline is extended to three months from when HMRC issues a return or notice.