Israel Aerospace Industries' Heron 1 and Elbit Systems' Hermes 900 are in the running. Nine other competitors to replace the Swiss air force's Ranger unmanned aerial vehicle didn't make the final selection round.
Sixteen of the original 28 Rangers, which first entered service in 2001, are still in service.
Swiss officials said the trials will take place in central Switzerland and will be conducted by Swiss air force and armasuisse specialists.
Selection of the winner is to be announced in the first half of 2014.
Acquisition of the new UAVs will be included in the government's Armaments Plan 2015.
The Hermes 900 is a medium-sized UAV designed for medium-altitude, long-endurance flights. It has a maximum speed of 137 miles per hour and a ceiling of 30,000 feet.
The Heron 1, which also has a ceiling of 30,000 feet, has a flight endurance of as much as 52 hours.