This is a list of former oceans that disappeared due to tectonic movements and other geographical and climatic changes. In alphabetic order:

• Bridge River Ocean, the ocean between the ancient Insular Islands (that is, Stikinia) and North America
• Cache Creek Ocean, a Paleozoic ocean between the Wrangellia Superterrane and Yukon-Tanana Terrane
• Iapetus Ocean, the Southern hemisphere ocean between Baltica and Avalonia
• Kahiltna-Nutotzin Ocean, Mesozoic
• Khanty Ocean, the Precambrian to Silurian ocean between Baltica and the Siberian continent
• Medicine Hat Ocean, a small Proterozoic ocean basin
• Mezcalera Ocean, the ocean between the Guerrero Terrane and Laurentia
• Mirovia, the ocean that surrounded the Rodinia supercontinent
• Mongol-Okhotsk Ocean, the early Mesozoic ocean between the North China and Siberia cratons
• Oimyakon Ocean, the northernmost part of the Mesozoic Panthalassa Ocean
• Paleo-Tethys Ocean, the ocean between Gondwana and the Hunic terranes
• Pan-African Ocean, the ocean that surrounded the Pannotia supercontinent
• Panthalassa, the vast world ocean that surrounded the Pangaea supercontinent, also referred to as the Paleo-Pacific Ocean
• Pharusian Ocean, Neoproterozoic
• Poseidon Ocean, Mesoproterozoic
• Pontus Ocean, the western part of the early Mesozoic Panthalassa Ocean
• Proto-Tethys Ocean, Neoproterozoic
• Rheic Ocean, the Paleozoic ocean between Gondwana and Laurussia
• Slide Mountain Ocean, the Mesozoic ocean between the ancient Intermontane Islands (that is, Wrangellia) and North America
• South Anuyi Ocean, Mesozoic ocean related to the formation of the Arctic Ocean
• Tethys Ocean, the ocean between the ancient continents of Gondwana and Laurasia
• Thalassa Ocean, the eastern part of the early Mesozoic Panthalassa Ocean
• Ural Ocean, the Paleozoic ocean between Siberia and Baltica

• Category:Historical oceans
• List of oceans – Limits of Earth's oceanic watersPages displaying short descriptions of redirect targets
• Paleocontinent – A distinct area of continental crust that existed as a major landmass in the geological past
• Paratethys – Prehistoric shallow inland sea in Eurasia
• Piemont-Liguria Ocean – Former piece of oceanic crust that is seen as part of the Tethys Ocean
• Superocean – Ocean that surrounds a supercontinent, an ocean that surrounds a global supercontinent
• Valais Ocean – Subducted ocean basin. Remnants found in the Alps in the North Penninic nappes.