U.S. FIFTH FLEET AREA OF OPERATIONS (Dec. 22, 2017) – Marines and Sailors with USS San Diego and embarked 15th Marine Expeditionary Unit pass boxes during a replenishment at sea. San Diego, with the embarked 15th Marine Expeditionary Unit, is deployed to the U.S. 5th Fleet area of operations in support of maritime security operations to reassure allies and partners and preserve the freedom of navigation and the free flow of commerce in the region. - U.S. FIFTH FLEET AREA OF OPERATIONS (Dec. 22, 2017) – Marines and Sailors with USS San Diego and embarked 15th Marine Expeditionary Unit pass boxes during a replenishment at sea. San Diego, with the embarked 15th Marine Expeditionary Unit, is deployed to the U.S. 5th Fleet area of operations in support of maritime security operations to reassure allies and partners and preserve the freedom of navigation and the free flow of commerce in the region.