A submarine is a watercraft capable of independent operation underwater. It differs from a submersible, which has more limited underwater capability. The term most commonly refers to a large, hollow, crewed and autonomous vessel.
- The NATO radio station at Anthorn in Cumbria
- The tracking tower on Mullach Sgar, St. Kilda
- Warsaw Radio Mast
- Anthorn Radio Station
- Rugby Radio Station
- Criggion Radio Station
- Lualualei VLF transmitter
- Kilo-class submarine
- November-class submarine
- Delta-class submarine
- Ballistic missile submarines
- Estonia did have a submarine in 1937!
- SOSUS sonar buoy line
- Hotel-class submarine
- USS Nautilus (SSN-571)
- USS Thresher (SSN-593)
- Soviet submarine U 137
- Whiskey-class submarine
- Type 209 submarine (FRG)
- USS Cobbler (SS-344)
- USS Hawkbill (SS-366)
- USS Tiru (SS-416)
- USS Ronquil (SS-396)
- USS Chivo (SS-341)
- USS Atule (SS-403)
- USS Remora
- PNS Ghazi
- INS Kursura (S20)
- ARA San Luis (S-32)
- USS Greenfish (SS-351)
- USS Pickerel (SS-524)
- USS Cobbler (SS-344)
- Tang-class submarine
- Whiskey class submarine
- Daphné-class submarine
- Oberon-class submarine
- Han class nuclear submarine
- Type XXI submarine (Elektroboote)
- British Porpoise-class submarine
- Foxtrot-class submarine
- Periscope
- Submarine snorkel
- Harpoon (missile)
- Mark 45 torpedo (nuke)
- Delta IV Class submarine
- Radar
- Sonar
- Radome
- Torpedoes
- Operation Behemoth
- Mark 45 nuclear torpedo
- Passive Underwater Fire Control Feasibility System (PUFFS)
- Greater Underwater Propulsion Power Program (GUPPY)
- The sinking of Soviet submarine K-27
- The reactor explosion on-board Soviet submarine K-431
- The Soviet Submarine K-19 accident
- Ohio-class ballistic missile submarine