A sea is a large body of salt water. All seas are connected with oceans. An ocean is a major body of saline water. A sea is also used sometimes to describe a large saline lake.
Atlantic Ocean
In Mediterranean Sea:- Aegean Sea, Mirtoon Sea, Sea of Crete, Thracian Sea, Adriatic Sea, Alboran Sea, Balearic Sea, Catalan Sea, Cilician Sea, Gulf of Sidra, Ionian Sea, Levantine Sea, Libyan Sea, Ligurian Sea, Sea of Sardinia, Sea of Sicily, Tyrrhenian Sea.
In Baltic sea:- Archipelago Sea, Bay of Bothnia, Bothnian Sea, Central Baltic Sea, Gulf of Bothnia, Gulf of Finland, Gulf of Riga, Oresund Strait, Sea of Åland.
Others:- Argentine Sea, Bay of Biscay, Bay of Campeche, Bay of Fundy, Black Sea, Caribbean Sea, Celtic Sea, Chesapeake Bay, Davis Strait, Denmark Strait, English Channel, Gulf of Guinea, Gulf of Maine, Gulf of Mexico, Gulf of St. Lawrence, Gulf of Venezuela, Irish Sea, Labrador Sea, Marmara Sea, North Sea, Norwegian Sea, Sargasso Sea, Sea of Azov, Sea of the Hebrides, Wadden Sea.
Arctic Ocean
Amundsen Gulf, Baffin Bay, Barents Sea, Beaufort Sea, Bering Sea, Chukchi Sea, East Siberian Sea, Greenland Sea, Hudson Bay, James Bay, Kara Sea, Kara Strait, Laptev Sea, Lincoln Sea, Prince Gustav Adolf Sea, Pechora Sea, White Sea.
Southern Ocean
Amundsen Sea, Bass Strait, Bellingshausen Sea, Cooperation Sea, Cosmonauts Sea, Davis Sea, D’Urville Sea, Drake Passage, Great Australian Bight, Gulf St Vincent, King Haakon VII Sea, Lazarev Sea, Mawson Sea, Riiser-Larsen Sea, Ross Sea, Scotia Sea, Somov Sea, Spencer Gulf, Weddell Sea.
Indian Ocean
Andaman Sea, Arabian Sea, Bay of Bengal, Gulf of Aden, Gulf of Oman, Laccadive Sea, Mozambique Channel, Persian Gulf, Red Sea, Timor Sea.
Pacific Ocean
Arafura Sea, Banda Sea, Bering Sea, Bismarck Sea, Bohai Sea, Mindanao Sea, Camotes Sea, Celebes Sea, Ceram Sea, Chilean Sea, Sea of Chiloé, Coral Sea, East China Sea, Flores Sea, Gulf of Alaska, Gulf of California, Gulf of Carpentaria, Gulf of Thailand, Halmahera Sea, Java Sea, Koro Sea, Molucca Sea, Philippine Sea, Salish Sea, Savu Sea, Sea of Japan, Sea of Okhotsk, Seto Inland Sea, Sibuyan Sea, Solomon Sea, South China Sea, Sulu Sea, Tasman Sea, Visayan Sea, Yellow Sea.
Landlocked seas
Aral Sea, Caspian Sea, Dead Sea, Sea of Galilee, Great Salt Lake, Salton Sea.