Not in the US version yet..

It is now ^-^ North American version now has this item, if you go to the functions tab and look up Equipment it'll come up.

So is it available only in Cash Shop? Is there any way of getting it without cash? Quests.. Or...

IMPORTANT:
It will make such costume bound to the character, also you will not be any longer able to move it to your bank

https://www.youtube.com/watch?v=V4DCjWvka5U

You're welcome

咕嘟咕嘟潛水服 可轉換成珍珠服裝，但不能加熱變更為可鑲嵌在珍珠服裝的水晶。