He will fit into Taylor's side at right-back, although the 6ft former England Under-21 can play in the middle of defence as well.
He made 13 Premiership starts for Tottenham Hotspur after joining them as a trainee, but was released at the end of his contract this summer. Tigers boss Taylor said that he "honestly couldn't believe" Thelwell was going free, and said he was "delighted" to bring him to the KC Stadium.