Underwater environment
Undersea Trilogy
Undersea and Hyperbaric Medical Society
Pacific Undersea Gardens
Undersea Kingdom
United States Naval Undersea Museum
Hawaii Undersea Research Laboratory
Japan–Korea Undersea Tunnel
Atlantic Undersea Test and Evaluation Center
Undersea mountain range
Undersea (EP)
The Undersea World of Jacques Cousteau
Aktio–Preveza Undersea Tunnel
Integrated Undersea Surveillance System insignia
The Undersea Adventures of Captain Nemo
The Little Mermaid: Ariel's Undersea Adventure
Undersea Adventure
Tongyeong Undersea Tunnel
The Undersea Environment
National Undersea Research Center for the North Atlantic and Great Lakes
Mobile Inshore Undersea Warfare Unit
Penang Undersea Tunnel
Jeju Undersea Tunnel
Oregon Undersea Gardens
National Institute for Undersea Science and Technology
National Undersea Research Program
Poseidon Undersea Resorts
Doraemon: Nobita and the Castle of the Undersea Devil
Undersea Girl
Howard Lovecraft and the Undersea Kingdom
Underwater tunnel
Morning Undersea
Naval Undersea Warfare Center
Tom Swift and His Undersea Search
Black Sea undersea river
Underwater habitat
2009 Tonga undersea volcanic eruption
SACLANT ASW Research Centre
List of submarine-borne aircraft
Underwater warfare
Dennis Chamberland
Submarine communications cable
Undersea Super Train: Marine Express
The Silent World: A Story of Undersea Discovery and Adventure
Svalbard Undersea Cable System
ALBA-1
SOSUS
General Bathymetric Chart of the Oceans
The Underseas Explorers
Autonomous underwater vehicle
United States Board on Geographic Names
List of international submarine communications cables
CURV
Diving medicine
Submarine earthquake
Centre for Maritime Research and Experimentation
Submarine power cable
The Little Mermaid (franchise)
Submarine pipeline
Project FAMOUS
Submarine volcano
Seamount
The Little Mermaid (TV series)
Dive computer
Submarine cable
Deep-sea exploration
List of underwater explorers
List of submarine topographical features
Remotely operated underwater vehicle
Turbidity current
Brine pool
Oceanography
Unnamed volcano (Ibugos)
Overflow (oceanography)
Deep sea mining
Ace (military)
Penghu
Ocean bank
Submarine landslide
Underwater archaeology
Coral World Underwater Observatory
Submarine canyon
Nautical chart
Mid-ocean ridge
Nord Stream pipelines sabotage
U-boat
Ocean current
Fédération Française d'Études et de Sports Sous-Marins
Namco