 Letheren went on trial with Dundee, with Manager John Brown saying he had done well.After making an appearance in a pre-season friendly, as a trialist, during which he suffered a thigh injury, it was then announced on 9 July 2013, that Letheren had signed a contract with Dundee.Letheren played as first-choice goalkeeper for Dundee throughout all of the 2013–14 season.