[1] The UOE was formerly garrisoned in the Tercio de Armada in San Fernando, Cádiz and operated under the direct control of the Admiralty and Special Naval Warfare Command.

For these purposes, the UOE employed a wide range of naval and other military platforms, including submarines, frigates, soft- and rigid-hull inflatable boats, land vehicles, as well as helicopters and airplanes for airborne insertions.

In 1967, using the US Navy SEALs and British SBS as its guides,[citation needed] the unit expanded its mandate and range of skills to include combat diving, underwater demolitions, airborne insertions and direct action missions.

After completing basic training and having served in a conventional unit, candidates aspiring to attain the "green beret" must undergo comprehensive medical and psychological reviews as well as physical trials, and then, if approved, pass a selection course (Capacitación).

Since then, the unit has been reported to have participated in the fight against Basque ETA violence inside Spain[4] (though today this is strictly the preserve of civilian police forces).

Also, in December 2002, while participating in Operation Enduring Freedom in the Indian Ocean, UOE commandos stormed a suspect North Korean vessel, the So San, transporting a shipment of SCUD missiles destined for Yemen.