Ryan moves to Lens in a permanent transfer, signing a contract to June.
Lens chief Pierre Dreossi said: "With 454 professional matches, Mathew Ryan is an important reinforcement for our team. This renowned goalkeeper has established himself for more than a decade as one of the best players in Australia, even on the Oceanian continent.
"Having played on European pitches during his various experiences in La Liga, Premier League, La Liga, Eredevisie or recently in Serie A, Mathew has built up an important background, as evidenced by his 66 appearances in UEFA competitions. Captain of the Australian team, he has also distinguished himself by participating in the last three World Cups.
"A complete goalkeeper, recognized for his leadership and his values, Mathew perfectly corresponds to the profile sought to strengthen the goalkeeping squad."