The vastly-experienced defender links up with manager Jamie Godbold again after previously signing him whilst at AFC Sudbury in 2016.
Tann has played at a whole host of clubs including Cambridge United where he enjoyed six seasons from 1999-2005, Notts County and Leyton Orient.
Godbold said after completing the signing: "I am delighted to bring Tanny to Lowestoft Town. Having worked with him before, his leadership, professionalism and experience will be hugely beneficial in developing our young players both on and off the pitch."
Tann has connections to the club already as he is cousins with ex-Trawlerboys Ryan and Rossi Jarvis.
Updated 10:17 - 9 Jun 2018 by Sean Galea-Pace