Military police perform assigned military law enforcement duties to uphold the criminal justice system, maintain good order and discipline, and support the commander's law enforcement and security requirements in peacetime and combat operations. Typical duties include foot and motorized patrol, control of pedestrian and vehicular traffic, flightline security, crime prevention/physical security, desk sergeant, communications dispatcher, squad leader, operations sergeant, platoon sergeant, and provost sergeant billets. MOS 5811 is very demanding in that the military police are confronted with every form of violation and criminal liability, misdemeanor through felony.

Master-At-Arms (MA) provide waterborne and land security, aircraft and flight line security, strategic weapons and cargo security, maritime security and platform protection; conduct customs operations, corrections operations, detainee operations, and protective service operations; perform force protection, physical security and law enforcement; organize and train personnel in force protection, physical security, law enforcement, and weapons proficiency; develop plans for physical security and force protection enhancement of Navy bases, installations, property, and personnel; and assist commands in conducting terrorist threat analysis and implementing defensive measures.