Can you dive into the water by the docks of my home city of Seattle? Can you dive into the water by the docks of New York? How about London? Tokyo? No?

You would die. Oceanfront water is horrible in front of populace’s. You have to avoid the docks, because riptides will drown you, and you also have to avoid boats, massive waves, and propellers. There’s too many dangers.

No you should not be able to swim in Limsa Lominsa.