Most mounts are ground and flying mounts, meaning that they will actually slow down when submerged in water.
Aquatic mounts, on the other hand, will greatly increase your movement speed while underwater.
Ride your own amphibious salamanther by learning how you might find a Coralscale Salamanther mount in WoW: Dragonflight.
These three mounts are the Abyssal Seahorse, the Subdued Seahorse, and the Sea Turtle.
Abyssal Seahorse
The first, and easiest, aquatic mount to get is theAbyssal Seahorse.
Known as the Abyssal Seahorse in Cataclysm, you simply have tocomplete the introductory quests to Vashj’ir.
The quest"The Abyssal Ride" in the Kelp’thar Forestof the undersea subcontinent awards this mount.
The Abyssal Seahorse hasa matching companion pet called Sea Pony.
Poseidus is an extremely rare mob thatcan spawn in five areas.
Four of these areas are in the Shimmering Expanse of Vashj’ir.
One spot it can spawn is in the middle of the red-tingedGlimmerdeep Gorge.
Another one is in the drownedRuins of Thelserai Temple.
It can also spawn amidst the kvaldir ofBiel’aran Ridge.
The last spot it can spawn within the Shimmering Expanse is theNar’shola Terraceof the Ruins of Vashj’ir.
The last spot that Poseidus can spawn is in theAbyssal Depths, the deepest part of Vashj’ir.
Here,it can be found near the southern end ofUnderlight Canyon.
Here’s how to complete the Wake Me Up meta-achievement in the Waking Shores zone.