A Hero's Call: Vashj'ir

Quest: A Hero's Call: Vashj'ir in Stormwind. It was on the call board.
This is the major underwater section in the World of Warcraft Cataclysm expansion.

Go to Stormwind Docks at the harbor and turn in to Recruiter Burns.

Pick up the quest: Call of Duty and wait around for the movie sequence to begin.

Here's the actual quest: Call of Duty.

Ahhh, it's a sea monster.

Wake up nearly dead in the Briny Cutter.

Turn in the quest, Call of Duty to Erunak Stonespeaker from the Earthen Ring.

He will give the quest Sea Legs.

That water breathing will really help lol.

Erunak Stonespeaker will give you the quest Pay It Forward. Rescue 6 drowning soldiers.

Next, he gives you the quest, Rest for the Weary.

Talk to Captain Taylor.

Captain Taylor will give you the quest, Buy us some time... go kill Nagas

Next, he gives you the quest, Traveling on our Stomachs.

While I was out killing the crabs I got this quest, Once More With Eeling.

While I was doing the Once More with Eeeling quest, I looted the tattered treasure map, and it gave the quest The Horde's Hoard.

Captain Taylor will give you another quest : To Arms, basically go collect pieces of armor

 

 

 

He will aslo give you the quest, S.E.A.L Stormwind Elite Aquatic and Land Forces :)

This is the last opening quest in Vashj'ir: On Our Own Terms: have fun killing the Nagas.

Many more underwater quests after this, but these should get you started.