Vashj'ir is an underwater zone. Players receive underwater breathing, swim speed buffs, and eventually a sea horse mount early on in questing to make transportation easier. Players learn about the history of the Highborne, as this city was home to Lady Vashj before the Sundering. Players learn about the threat of Ozumat, culminating in a battle between Neptulon and the naga.

This zone was originally intended to have further dungeons and quest hubs in 4.2, but that was dropped in favor of developing Firelands and the Molten Front.

Kelp'thar Forest is the first subzone players reach when questing in Vashj'ir. It has tropical underwater life and is closer to the surface than other subzones. Quests introduce the threat of the naga while also reacquainting the player with stranded members of the Zul'Aman exploratory crew.

The Shimmering Expanse is the second subzone of Vashj'ir. It contains The Earthen Ring quartermaster in Silver Tide Hollow, the only flight points in the zone, and tons of Azshara's Veil. In this section, players learn about the highborne's past and the threat of the naga through the eyes of Battlemaidens.

Poseidus, who drops Reins of Poseidus, is mostly likely to spawn in this subzone too.

Abyssal Depths is the last, and darkest zone, players reach when questing in Vashj'ir. They are home to the ancient god L'ghorek, which the Twilight Hammer is siphoning energy from to be prepared when fighting Neptulon in the future.