Yes. Naval mines are still used: the U.S. Navy keeps two types of sea mines in service and is developing several more, according to its official fact file.
A sea mine is a self-contained explosive device designed to destroy ships, submarines and other vessels. Navies use mines to deny an enemy access to parts of the ocean or to funnel ships into certain areas, at low cost. The Navy’s in-service mines are the aircraft-laid Quickstrike family (Mk 62, Mk 63 and Mk 65), first deployed in 1983, and the Mk 67 Submarine Launched Mobile Mine, first deployed in 1987. The Mk 62 and Mk 63 are converted 500-pound and 1,000-pound bombs laid in shallow water, while the Mk 65 is a 2,000-pound mine with a thin-walled case. Mines now in development include the Mk 68 Clandestine Delivered Mine, the Hammerhead, a moored torpedo for intermediate and deep water, and the Quickstrike Extended Range. Mines also have a long record: in World War II, U.S. aircraft dropped more than 12,000 mines in Japanese shipping routes, sinking 650 ships.
Source: U.S. Navy fact file, US Navy Mines
Image: Sailors load a Mk 65 Quickstrike mine, U.S. Navy photo, public domain, via Wikimedia Commons.