The only way to get there is with Captain Max. He can take you there from Liberty Bay. He also rents the Helmet of the Deep, which is needed to walk underwater. In order to get the ability to travel with Captain Max you need to do The Explorer Society Quest.
|Captain Max||Ship Captain||✓||Liberty Bay on one of the eastern Boats at the dock (here), and on a boat above Calassa (here).|
|Massive Water Elemental||1100||1250|