Submarine-Launched Cruise Missile or SLCM's are cruise missiles that deliver conventional and/or nuclear payloads and are launched from ships or submarines. Current versions are typically standoff weapons which are used to attack predetermined land targets.
Four US Navy ballistic missile submarines (SSBN) have been converted to SSGNs. They are able to launch up to 144 Tomahawk cruise missiles to any number of targets. The advantage that the submarines have over guided missile destroyers and cruisers is the ability to remain undetected and launch while submerged.
The previous US Navy cruise missile submarines (4 SSG and 1 SSGN) deployed with the Regulus missile from 1958 until retired in 1964 with the arrival of the Polaris missile submarines in the Pacific.
Specific types of SLCMs include: