It is responsible for conducting air-sea rescue, amphibious reconnaissance, amphibious warfare, black operation, bomb disposal, CBRN defense, coastal raiding, counterterrorism, direct action, executive protection, hostage rescue, irregular warfare, ISTAR, long-range penetration, JTAC, manhunt high-value target, maritime sabotage, mountain rescue, naval boarding, operation behind high risk enemy lines, special operations, special reconnaissance, tracking targets, underwater demolition, unconventional warfare, other missions in support of Portuguese and NATO armed forces.

DAE's mission and training are similar to their American counterparts DEVGRU and the British SBS.

Students receive instruction in: basic combat diving techniques, EOD and underwater demolitions.

Phase 2 instruction includes courses on: escape and evasion techniques, advanced driving, mountaineering, offensive operations, parachuting training and basic English.

After this tough selection, COEMAR starts, which lasts 18 weeks and is divided into three phases: During and after COEMAR, DAE's military personnel receive training in areas as varied as: DAE conducts regular training exercises with its NATO counterparts, including the United States Navy SEALs, Special Naval Warfare Force (FGNE), French Commandos Marine, JW GROM, Lithuanian Special Operations Force as well as the respective naval counter-terrorist units.