USS Swordfish (SS-193), a Sargo-class submarine, was the first submarine of the United States Navy named for the swordfish, a large fish with a long, swordlike beak and a high dorsal fin. She was the first American submarine to sink a Japanese ship during World War II.

The Sargo-class submarines were among the first United States submarines to be sent into action after the Japanese attack on Pearl Harbor, starting war patrols the day after the attack, having been deployed to the Philippines in late 1941. Similar to the previous Salmon class, they were built between 1937 and 1939. With a top speed of 21 knots, a range of 11,000 nautical miles (20,000 km), and a reliable propulsion plant, along with the Salmons they were an important step in the development of a true fleet submarine. In some references, the Salmons and Sargos are called the "New S Class", 1st and 2nd Groups.