Self assessment deadlines Two self assessment deadlines are approaching: 5th October 2020 For those individuals who have not previously completed a tax return but need to report a liability for 2019/20. 31st October 2020 For those individuals who have previously submitted 'paper' self assessment tax returns the deadline for the 2019/20 return is 31 October 2020. Returns submitted after that date must be submitted electronically or they will incur a minimum penalty of £100. The penalty applies even when there is no tax to pay or the tax is paid on time. If you would like any help with the completion of your self assessment tax return, please do get in touch. Internet link: HMRC deadlines