Tuqiri, who recently returned to Sydney following a three-month stint with Irish side Leinster, left the Wests Tigers at the end of the last season having made just four appearances in 2013 after struggling to recover from a broken arm.
The 34-year-old former Brisbane and Queensland winger returned to the NRL in 2010 after an eight-year stint in the 15-man code and enjoyed an excellent season, playing 27 games and crossing for 18 tries.
However, he has played just 25 times since 2011 due to injury problems and had looked to see out his career in Europe before Souths coach Michael Maguire offered him a one-year deal.
"Lote has played the game at the highest level for many years and the experience he will bring to our young backline will be invaluable," Maguire said.
"He's expressed a desire to continue to play top level rugby league in our discussions and he will have a chance to be selected in our top 17 based on his performances as we head towards round one.
"We're looking forward to having him join the side for pre-season training and seeing the influence he can have on the young players we have in our squad."
Tuqiri said he's excited by the challenge of playing for a Souths side that will be one of the favourites to win the premiership this year.
"I'm really excited to be back and to be part of a club that's on the way up," Tuqiri said.
"The club has some very talented youngsters and some of the superstars of the game, and it's exciting for me to be part of the Rabbitohs now."