First-choice when fit, Lonnis is a fine shot-stopper who did much to help Costa Rica secure their World Cup berth during his nine appearances in qualifying.
With sharp reflexes, Lonnis has a reputation for spectacular saves and penalty stops.
However, manager Alex Guimaraes has urged him to work on his taking of crosses.
Was at fault in the recent friendly with Japan when he allowed a cross from Tomokazu Myojin to float over his head and into the net.
The 36-year-old has been capped around 70 times for his country and will bring all that experience to the fore in the finals.