Lozada, capped 22 times by his country, joins from French Top 14 side Agen and has immediately linked up with the squad this week at a pre season camp in France.
Lozada adds experienced depth to the pool of talented locks already at Wasps which includes Tom Palmer, Joe Launchbury, Kearnan Myall and James Cannon.
Having made his debut in 2006, Lozada most recently played for Argentina in June against England and he represented his country at the 2007 World Cup. He has previously represented Toulon and Edinburgh.
London Wasps Director of Rugby Dai Young said: “It was important for us to add another lock to the mix ahead of the season and I think we have a very strong group of players there who are all going to push each other hard for selection. Esteban is bringing solid international experience with him and we’re looking forward to seeing what he can bring us.”