Both are riflemen in the same unit. They have pleaded not guilty.
U.S. Border Patrol agents say smugglers lure people with offers of quick cash if they drive migrants through a heavily secured US border zone near San Diego.
An investigation has led to the arrest of 16 Marines following an investigation into human smuggling.
The Marine Corps said the arrests at Camp Pendleton, California, were carried out during a battalion formation Thursday morning at the base, north of San Diego. It is about 55 miles (90 kilometers) from the U.S.-Mexico border.