Major oil and trade sea lines of communication within this area are critically important to the economic health of the United States and friendly nations throughout the Pacific Rim region.

The fleet provides maritime homeland defense, regional security, and humanitarian operations support through integrated naval and coastguard forces acting as a single Sea Service.

Third Fleet's air forces comprises more than 400 Navy aircraft, including Boeing F/A-18 Super Hornets, Northrop Grumman E-2C Hawkeyes, McDonnell Douglas AV-8B Harrier II, Bell AH-1Z SuperCobra and Sikorsky SH-60 Seahawk helicopters.

As the Third Fleet, it took part in the Palau Islands campaign of September–November 1944 and the Philippines campaign of 1944–1945, defeated the Imperial Japanese Navy in two of the four major actions – the Battle of the Sibuyan Sea and the Battle off Cape Engaño – that made up the Battle of Leyte Gulf in October 1944, encountered the damaging Typhoon Cobra in December 1944, endured Typhoon Connie in June 1945, and took part in the war's final operations in Japanese waters in the summer of 1945, launching air attacks on Tokyo, the naval base at Kure, and the island of Hokkaidō and bombarding several Japanese coastal cities with naval gunfire.

The Third Fleet remained in Japanese waters until late September 1945, when its ships were directed to proceed to the United States West Coast.

[9][10] Third Fleet's primary mission is one of conflict deterrence, but in the event of general war, it would conduct prompt and sustained combat operations at sea.

Such operations would be executed well forward and early in a conflict to carry out the primary wartime mission of Third Fleet—the defense of the western sea approaches to the United States, including Alaska and the Aleutian Islands.

[citation needed] In peacetime, Third Fleet continually trains Navy and U.S. Marine Corps forces for their expeditionary warfare mission.

"If that were the case, the assumption is that [Aucoin] and his team would be pretty busy up there.. working for General Brooks [ComUSFK/CFC/UNC] and 3rd Fleet would be available to provide that command element to handle whatever else may happen in the Pacific Fleet AOR ...be it a major humanitarian disaster requiring that level of [joint task force] three-star commander, be it some scenario, maritime security issue in the South China Sea.

In April 2016, Vice Admiral Tyson deployed a three-ship Surface Action Group of warships (Momsen, Spruance, and USS Decatur (DDG-73))[12]) to the Western Pacific.

On Oct. 21, one of them, the destroyer USS Decatur conducted a "Freedom of Navigation" passage near the Paracel Islands, separately claimed by the PRC, Vietnam and Taiwan.

As Tyson partially acknowledged during her WEST 2017 conference remarks, "the Chinese know that this administrative (and) operational innovation is directed at them," said Toshi Yoshihara, a U.S.