Hikari Kohinata "Pikari"
- Genki Girl: So much so it`s where she got her nickname.
- Living Emotional Crutch: Acts as this for the very shy Dotty at times, though when Dotty is made aware that she's using Pikari this way she starts to grow a backbone.
- Romantic Two-Girl Friendship: With Dotty.
- The World Is Just Awesome: There is nothing in this world that this girl does not enjoy.
Futaba Ooki "Teko" ("Dotty")
- Audience Surrogate: She is the one usually getting all the diving stuff explained to her and for those in the audience with no diving experience.
- Camera Fiend: During most activities she can be seen taking pictures.
- Clingy Jealous Girl: A light example towards Pikari.
- The Load: She is the only member of the diving club without an Open-Water license and at first doesn't even know how to swim.
- Romantic Two-Girl Friendship: With Pikari.
- The Watson: When it comes to diving
- Cool Teacher: Tells her students to have fun as much as possible, and it can be hard to tell her apart from her diving students
- Stern Teacher: But she is very strict when it comes to actual teaching, bordering on sadist, especially when teaching diving.
- Genki Girl: While being in her early twenties she can give even Pikari a run for her money.
- Hot Teacher: Does not seem to be much older than her students, and quite a bit of fanservice comes from her.
- Sensei-chan: Normally a responsible adult, but she can be pretty childish sometimes too. Like, getting really into a race across town, bending the rules of a children's game so she wins, and not wanting to pay her debts.
- Cat Girl: Not really, but she does tend to act and look cat like. Her Face Fault is even a Cat Smile
- Cool Big Sis: To the point that everyone refers to her as Ane-san, or Big Sis
- D-Cup Distress: Has problems with her size such as having to wear multiple swimsuit tops and accidentally giving a show when buttons pop.
- Kick Chick: When mad or annoyed (or just for the heck of it) she'll kick her brother. Often it's a flying kick.
- The Stoic: Unlike the easily excited girls and teacher Makoto tends to be the calm voice of reason.