This dress is a L$3 hunt prize on the Save the Sea Hunt 4. The hunt runs until the end of the month, so you have plenty of time!
The dress is sized to fit Lara, Lara Petite, Legacy, Freya, Altamura, Hourglass, and Erika. It comes with a ten texture HUD, with of course some sea themed patterns, a few florals, and a plain red.