Tax Season 2016 is expected to start very soon. Up to 8 days before Tax Season 2015 did. IRS announced official first day to file taxes in 2016 recently. The IRS will begin accepting 2015 tax returns electronically on Jan. 19, 2016. Mailed 2016 Tax Returns will begin processing around the same time. We have updated this date based on the IRS recent notice here.