Family Name: NellaFantasia

Region (NA/EU): NA

Swimming underwater is abysmal without the corsair, shark/fish costume, or a swimsuit. So at least give us something else that can allow us to swim underwater faster. 

There's plenty of content underwater that could be reached by swimming, such as the Sea Palace, Sycraia Underwater Ruins, some gathering spots, quests, & sailing dailies. 

This may be a niche request, but at least it would give BDO an official underwater mount. 

You could keep the dine looking as it does, giving it a bubble similar to the skill "Protection of Okaira" while underwater.

Or remove the bubble and give it a "run/swim" animation.

Or

You could transform it into a hippocampus/seahorse similar to below: