From WoWWiki

The Forbidding Sea is a largely unexplored portion of the Great Sea along the eastern coast of the Eastern Kingdoms, sometimes noted by travelers on the coasts of the Hinterlands, Arathi Highlands and Swamp of Sorrows. Most of these waters are made by many impassable mountain ranges on the long eastern coast of the continent, east of Khaz Modan.

Subzones of Arathi Highlands

Boulder'gor • Boulderfist Hall • Boulderfist Outpost • Circle of East Binding • Circle of Inner Binding • Circle of Outer Binding • Circle of West Binding • Crypt • Dabyrie's Farmstead • The Drowned Reef • Drywhisker Gorge • Faldir's Cove • Forbidding Sea • Go'Shek Farm • Hammerfall • Northfold Manor • Refuge Pointe • The Sanctum • Stromgarde Keep • Thandol Span • Thoradin's Wall • The Tower of Arathor • Witherbark Village

Subzones of The Hinterlands
Aerie Peak • Aerie Peaks • Agol'watha • Altar of Zul • Bogen's Ledge • The Creeping Ruin • Featherbeard's Hovel • The Forbidding Sea • Hiri'watha • Jintha'Alor • Overlook Cliffs • Plaguemist Ravine • Quel'Danil Lodge • Revantusk Village • Seradane • Shaol'watha • Shadra'Alor • Shindigger's Camp • Skulk Rock • Valorwind Lake • Wildhammer Keep • Zun'watha

Subzones of the Isle of Quel'Danas
The Bloodoath • The Dawnchaser • The Dawning Square • Dawnstar Village • The Dead Scar • The Forbidding Sea • The Great Sea • Greengill Coast • Magisters' Terrace • Shattered Sun Staging Area • Silvermoon's Pride • The Sin'loren • Sunwell Plateau • Sun's Reach • Sun's Reach Armory • Sun's Reach Harbor • Sun's Reach Sanctum

Subzones of Swamp of Sorrows
Fallow Sanctuary • The Forbidding Sea • Harborage • Itharius's Cave • Misty Reed Post • Misty Reed Strand • Misty Valley • Pool of Tears • The Shifting Mire • Sorrowmurk • Splinterspear Junction • Stagalbog • Stagalbog Cave • Stonard