Cobalt Plus: Hinano and Rei (Patreon)

At Kei's suggestion, she and Hinako decided to get some exercise by freediving through an offshore cave - a place she wanted to explore earlier but could not due to her responsibilities with the swim team. While reluctant at first, Hinako eventually decided to jump on board since she didn't have much of anything to do now that school was out. Eventually, both Kei and Hinako made it into a wide chamber in the cavern, but not without strain - the only entrance was a long, dark, and twisty. Even though both girls were in great physical shape, the journey was exhausting and they now had figure out how to time going back to the surface... 

Requester: https://www.patreon.com/MetalCar/creators

And please let us know if anyone wants to see this colored under Cobalt Premium.