Another dungeon underwater, see the map below where it is located.

Chests (10):

• Diamond Helm
• Diamond Bracers
• Defender
• Diamond Mail
• Diamond Gloves
• Behemoth Knife
• Blood Lance
• Protect Ring
• Lamia Harp
• Diamond Shield

Follow the map, collect all chests. You will be to change job to Thief in order to unlock the doors through out the dungeon. After you obtained Noah's Lute, you can either you Teleport or backtrack to get out.

Behind the waterfalls at number (7) is a hidden passageway leading to more chests.

Now go to Unei's Shrine, talk to her, and watch a scene. She will tell you that you need a new airship, Invincible.