Grand Blue

Grand Blue (グランブルー) is a diving shop owned by Toshio Kotegawa and the main setting of the series. It also doubles as a residence for the Kotegawas and Iori Kitahara.

Staffs

 * Toshio Kotegawa - Owner/Manager
 * Nanaka Kotegawa - Diving Instructor

Residents

 * Chisa Kotegawa - Peek a Boo member. First year student at Izu University.
 * Iori Kitahara - Peek a Boo member. First year student at Izu University.

Customers
An intercollegiate diving club that uses the establishment as their meeting point for club activities and the main source for equipment and services.
 * Peek a Boo
 * Shinji Tokita - Club member. Third year student at Izu University.
 * Ryūjirō Kotobuki - Club member. Third year student at Izu University.
 * Azusa Hamaoka - Club member. Third year student at Oumi Women's University.
 * Kōhei Imamura - Club member. First year student at Izu University.
 * Aina Yoshiwara - Club member. First year student at Oumi Women's University.
 * Kaya Mizuki - A famous voice actress.