"What do you say we go swimming together?" One of them said.
"Sounds lovely!" Joey answered.
As he followed them into the water; the brown skinned girl said, "I'm Maria, and this is Kasumi." She pointed to her Asian friend.
Wading out into the water, the girls dove beneath the surface and began to dolphin-kick out further. As clear as the water was, he couldn't make out any human shapes after the girls faded from view. Left alone, all Joey could think about was how he should've known better. "Of course they left, what pretty girl would honestly give me the time of day?" However, he did start growing concerned. Even if they did run, or swim off, they still should've resurfaced somewhere within view by now. Holding their breath was one thing, people have done that for a few minutes, but swimming as well, especially at the speed they were going? That was some exertion that demanded they took a breath by now.
"Maria!? Kasumi!?" Joey really started to worry, now. He took a deep breath and plunged his head beneath the water and gazed around, the saltwater slightly stinging his eyes. "There's no nearby rocks or outcroppings to conceal them; so where..." His thoughts were interrupted when a cute Japanese girl's face came into view. He spat bubbles from his mouth at it before jerking himself back above the surface.
Kasumi soon surfaced in front of him and spat water in his face before giving him a playful smile. Maria soon followed her as Joey sputtered and spat. "Where were you? I was worried!"
"We were underwater, of course!" Kasumi said.
"How do you hold your breath for so long?!" Joey asked.
"Who says we needed to?" Maria said.
"Uh, human physiology! You know; you breathe water, you die!"
"YOU breathe water, you die." Kasumi said before diving back into the water, trailed not by legs, but a long, copper-colored fishlike tail.
"WE, on the other hand..." Maria said as she followed her friend, deliberately showing her shiny, violet-colored tail. Taking a breath and peeking beneath the surface, you can see the two girls taking long, deep breaths of water; inhaling and exhaling. It was no trick, they were actually breathing water; these were genuine mermaids.
They resurfaced and spat water out to the side. Maria stroked Joey's cheek and said "Now the fun can REALLY begin!"