The 27-year-old Portuguese international has played more than 100 games and scored twice since joining the Premier League side in 2015.
“Cedric Soares is a new Inter player. The 27-year-old defender joins the Nerazzurri on loan from Southampton FC with the option to make the deal permanent,” Inter said in a statement.
Southampton said the “move further helps to achieve Ralph Hasenhuttl’s desire for a leaner squad, with the manager having also overseen the emergence of young right-back Yan Valery, as well as Kayne Ramsay, since his arrival at the club.”
Inter Milan are third in Serie A — 16 points behind leaders Juventus.
Download our app and read this and other great stories on the move. Available for Android and iOS.