The Inner Sea is a body of water that separates the mainland of the Imperial province of Morrowind from the large island of Vvardenfell. It stretches from the Bitter Coast and Ascadian Isles regions in western Vvardenfell all the way to Azura's Coast in the east. It meets the Sea of Ghosts twice: the two meld together near Azura's Coast, and again near the large and icy island of Solstheim northwest of Vvardenfell.
The Inner Sea was created after the giant volcano Red Mountain erupted and some of the landmass of Vvardenfell sank lower than sea level. The resulting crater was filled by the icy waters of the Sea of Ghosts, cooling the lava over time. Some reports place this event after the War of the First Council in 1E 668, referred to in the tales of numerous races—to the Nords it was The Year of Winter in Summer, to the Khajiit, Sun's Death. However, there are conflicting reports stating that there might have been earlier eruptions creating this change in landscape.
The main port of the Inner Sea on Vvardenfell is Ebonheart, with minor ports being Hla Oad, Gnaar Mok, Molag Mar, Tel Branora and the Imperial outpost of Seyda Neen with its lighthouse Grand Pharos guiding mariners. The Imperial Legion once held a strategic outpost called Fort Firemoth on an offshore island of the same name, but it was overrun by an undead army and never reclaimed.
The coast of Vvardenfell is rugged and treacherous, with shipwrecks scattered among the menhirs that protrude from the water. It has been a major center of smuggling operations by the Cammona Tong and other groups.
Early in the Fourth Era, Baar Dau crashed into Vivec and exploded, causing Red Mountain to erupt and opening a fissure to an active underwater volcano. The area of the sea where Vivec once stood is now known as Scathing Bay.