Marines from the 3rd Reconnaissance Company (Force Recon), come ashore during a demonstration.
Note the flippers carried by the Marines.
Force Recon Marines are experts in amphibious operations such as beach reconnaissance, during which the Marines check out a beach for suitability for an amphibious landing by the MEU(SOC) they are attached to.
Force Recon Marines must report on any obstacles, enemy presence as well performing a survey of the approaches to the beach, ensuring that the various USMC vehicles can travel across it, all whilst remaining undetected by anyone on the shore.