The sea was a large body of water that was found west of Alagaësia. Many exotic creatures, such as giant sea serpents, like the one Fundor fought, could be found in this body of water. There were many islands in the sea, such as Vroengard, Beirland, and Sharktooth Island. Most were uninhabitated. Pirates roamed the sea, pillaging ships and coastal towns. Ports like Teirm were built for sea travel.
There was also the North Sea (also called the Bay of Fundor), a smaller stretch of water in the north west of Alagaësia. In the first chapter of Murtagh, a passage says, "Rows of fishing boats with furled sails floated alongside the stone wharves, and with them, three deep-sea vessels with tall masts and broad hulls, ships capable of surviving passage around the northern tip of the peninsula that separated the bay from the ocean." This confirms the Bay of Fundor connects to the ocean by navigating around the northern coast of the spine however, it is implied that the journey is dangerous and only properly equip vessels can brave it. Additionally, this is the body of water that Ceunon was built upon. It was also the first sea that Horst had ever set his eyes upon.