Marina couldn't help but smile. While she had considered herself an accomplished swimmer before, this was a whole new level of mobility in the water.
After all, she could only hope to try and imitate a marine lifeform with two paddling legs and a monofin. Now her legs were completely gone, with where they would be replaced by a tail. And not just her legs merged together, but a genuine connected to spine and tailbone tail with a dorsal and caudal fin. Even her lungs were changed to be more like that of marine mammals, if her being underwater for several minutes with little issue was any indication.
That reminded her that she may as well take a breath.
She popped her head up, seeing that the beach that was once close was now distantly on the horizon. For a moment, she worried about swimming back to shore before remembering the obvious. After a quick breath, she returned under water to inspect her wetsuit. At least, that's what it was, right?
Well, if it was, she realized, it wasn't anymore. The logos, the collar or any endings, really any sight that the wetsuit was a piece of clothing was gone. She felt no sign that it was really able to be considered anything other than her new outer layer of skin. It kinda reminded her of that of a dolphin or eel.
While she had been pondering that, she noticed that further changes were happening, this time back to her arms and hands. While they had already become webbed earlier, her digits were growing longer and more indistinguishable from the webbing. It wasn't very long before the only ones that she could move separately from the others were her thumbs. While her new pectoral fins grew in length, her arms shrank steadily. Soon, they were basically just her forearms (but even shorter) with her pectoral fins/flippers having little claws of the end of them that reminded her of a Sea Turtle. She was still able to move what were once her thumbs slightly, giving her some ability to grip things still.
She continued to ponder what to do. While she greatly enjoyed the increased mobility in the water her pectoral fins gave her, she had to acknowledge that using her phone had now gone from merely difficult to next to impossible. And that was without going into even more changes, each making her more compatible with life in the ocean and less with life on land.