You see, Brigid and Fódlan have different customs when it comes to swimming.

As one would rightly guess, the lands of Brigid and Fódlan have rather different cultures and societies, and so, they have vastly different views between the two when it comes to many things such as customs and traditions. One of them being how they see nudity.

Fódlan for example, sees nudity as something improper and inmoral, with people being expected to be modest and pious, no thanks to the influence of the Church of Seiros that has upon it's culture and society. And as such, one is expected to wear a swimsuit to swim, with those who don't, being seen as crazy or perverts.

However, the same cannot be said for Brigid, who befitting it's reputation as an exotic warm island, does not see nudity as negative as fódlan, and indeed, it's pretty common for people to swim nude together without being ashamed of it, regarless of gender or social status. As such, swimsuits are pretty much nonexistent there.

Despite living in the empire for a couple years now, Petra was, above else, a native of brigid, and proud of that to boot. And so, as soon as she decided that she was gonna go for a swim, she began to take off her clothes piece by piece, until at last, she was left as naked as the day she was born.

And so, the naked Petra was left to admire the island's beautiful sands and shores, but as one would rightly think, her fódlan born classmates, wouldn't take naturally her nudity very well. And indeed, it seems that her time learning in Fódlan may have made Petra a bit more aware of her nudity, for as soon as she heard someone coming, she first reacted a bit hesitant.

"Petra !!?, why are you--", the voice said shocked as it came closer to her.