Iori Kitahara

Chisa Kotegawa

Chisa Kotegawa is Iori's cousin and a first-year mechanical engineering student at Izu University. Chisa appears to more level-headed and serious compared to other characters. She

Kouhei Imamura

A first-year Mechanical Engineering student at Izu University. He is Iori's best friend and a diehard otaku, perceived to be a lolicon by his acquaintances. He happens to be partic

Aina Yoshiwara

Aina is a first year at Oumi Women's University. She joins Grand Blue Diving Club after getting to know Iori and Kouhei. She is a really shy girl and hates having to expose her ski

Sakurako Busujima

She is a student at Oumi Women's University and the coworker of Iori Kitahara and Naomi Otoya. She has a crush on Otoya Naomi.

Azusa Hamaoka

Azusa Hamaoka is a third-year at Oumi University and is a part of the intercollegiate diving club with Izu University. Known for her very outgoing and exhibitionist personality, sh

Shinji Tokita

He is a third year Mechanical Engineering student at Izu University.

Ryuujirou Kotobuki

He is a third year Mechanical Engineering student at Izu University.

Nanaka Kotegawa

Iori's Elder Cousin. When Iori comes to Grand Blue he doesn't recognise her at first since she had become very beautiful and gets attracted to her only to find out later that she h

Yuu Mitarai

One of Iori's classmates at Izu University. Unlike most of the others, Yuu is in a relationship with his childhood friend Rie, which his friends immediately attempt to sabotage onc

Rie Oohashi

She is a first year student at Oumi Women's University and Yuu Mitarai's childhood friend.

Shinichirou Yamamoto

He is a first year Mechanical Engineering student at Izu University. He is a chubby young man with short hair parted in the middle. He mostly seen wearing a plain t-shirt under a s

Toshio Kotegawa

The owner of the diving shop Grand Blue and Iori's uncle. Toshio seems to have a jovial personality and is quite laid back, as he doesn't seem to mind all the havoc that the club m

Hajime Nojima

He is a first year Mechanical Engineering student at Izu University. Nojima is a tall and self-proclaimed handsome young man.

Kudou

The Captain of the Tennis Club "Tinkerbell" and a beautiful young man who is attracted to Azusa. Kudou is an arrogant womanizer that would do almost anything to achieve his goal. H

Kaya Mizuki

Famous voice actor and idol who is worshipped by Kouhei. Her real name is Maya.

Kenta Fujiwara

One of Iori's classmates at Izu University. A muscular man who is jealous of Iori supposedly getting Chisa's affection.

Kanako Iida

Aina's freshmen friend and a first year student at Oumi Women's University.

Keiko Suzuki

Aina's freshmen friend and a first year student at Oumi Women's University. She admits that whenever someone is innocent and pure, she feels the need to corrupt them.