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