Grand Blue Dreaming

Peek a Boo (Diving Club)

• Iori Kitahara (北原 伊織)
• Iori is a first-year Mechanical Engineering student at Izu University and a member of the diving club, despite never having learned to swim. Though he attempts to live an ordinary life, he frequently finds himself drawn into the club’s chaotic activities, which often involve drunken antics. Outwardly brash and carefree, he deeply values his relationships and suppresses his flaws when necessary. Despite his father’s adoption into the Kotegawa family, he considers Chisa and Nanaka as true siblings. His genuine demeanor gradually endears him to others, though his earlier immaturity sometimes causes friction. Once an aspiring musician, he now cringes at his past attempts at songwriting. Naturally athletic, he excels in sports requiring precision, though he tends to overcomplicate simple problems with absurd theories. He occasionally cross-dresses.[7][8]
• Chisa Kotegawa (古手川 千紗)
• Chisa is Iori’s cousin and classmate at Izu University, a composed and intelligent young woman devoted to diving. Unlike the other members of the Peek a Boo club, she maintains a reserved demeanor, avoiding their rowdy behavior and showing little interest in romance. Despite her disinterest, she frequently deflects advances from fellow students. Aspiring to become a dive instructor like her mother, she prioritizes diving above all else. To maintain her independence, she manipulates situations—even pretending to be in a relationship with Iori to deter suitors or retaliate when he helps others over her. Though she shares a love of diving with Iori, their dynamic shifts between warmth and frustration due to his loud personality. Her strained relationship with her mother leaves her emotionally guarded, causing her to become flustered in vulnerable moments.
• Kōhei Imamura (今村 耕平)
• Kōhei is Iori’s best friend and rival, an eccentric otaku who proudly wears anime-themed shirts. He enrolls at the university chasing an unrealistic dream of attracting high school girls, but is instead drawn into the Peek a Boo club. His obsession with anime distorts his social awareness, often leading him to misinterpret real-life situations through the lens of his favorite shows. Easily manipulated by references to famous female voice actors—especially Kaya Mizuki—he becomes a frequent target of the club’s pranks. Despite his absurd demeanor, he demonstrates unexpected resolve when his interests are threatened. Though his friendship with Iori is marked by playful antagonism and boisterous clashes, he remains deeply loyal when it counts. Hints suggest he hails from a wealthy background.
• Aina Yoshiwara (吉原 愛菜)
• Aina is a shy Ōmi Women’s College freshman who joins Peek a Boo after Iori and Kōhei defend her from bullying at her former tennis club. Nicknamed "Cakey" for her heavy makeup, she sheds this persona upon joining, revealing a timid nature that contrasts with the club's rowdiness. Though initially interested in Kōhei, she develops feelings for Iori after he avenges her. Her farm upbringing makes her adept at manual labor but self-conscious about her rural accent. Naive about romance and insecure about her body compared to Nanaka and Azusa, she paradoxically becomes wildly uninhibited when drinking.
• Ryūjirō Kotobuki (寿 竜次郎)
• A senior student at Izu and a member of Peek a Boo who often got himself and other club members drunk and naked. Kotobuki is just like Tokita both in appearance and in personality when they are partying, but Kotobuki can be surprisingly charismatic. He works as a professional bartender part-time.
• Shinji Tokita (時田 信治)
• A senior student at Izu and member of Peek a Boo who often got himself and other club members drunk and naked, Tokita is a muscular, laid-back college student who loves to party. However, just like the other members of PAB, he sincerely loves diving and takes the possible dangers seriously. To Iori's surprise, he has a girlfriend.
• Azusa Hamaoka (浜岡 梓)
• Azusa is a senior at Ōmi Women's College and one of the few female members in Peek a Boo's senior circle. Her natural sensuality leads younger members to assume she is sexually experienced, though her interests focus almost exclusively on Nanaka for comedic effect. While harboring unrequited feelings for Tokita, she avoids acting on them to preserve group harmony. Notoriously unconcerned with modesty, she frequently undresses without warning. She befriends Iori after mistakenly believing him to be bisexual, seeing him as a potential confidant. Despite her playful mischief that often creates humorous complications, she demonstrates genuine care and insight when helping others with personal problems.

Grand Blue (Diving Shop)

• Nanaka Kotegawa (古手川 奈々華)
• Nanaka is a diving instructor at Grand Blue and Chisa's older sister. A voluptuous yet reserved figure, she typically observes rather than participates in the diving club's rowdy activities. Her presence alone causes the members to moderate their usual drunken behavior. She states she would support Iori if he could make her sister happy. Ironically naive about sexual matters, she frequently finds herself in compromising situations with Iori and Azusa. She demonstrates terrifying physical strength when perceiving any threat to her bond with Chisa.
• Toshio Kotegawa (古手川 登志夫)
• The owner of the diving shop Grand Blue and Iori's uncle, as well as the father of Chisa and Nanaka.
• Kaya Mizuki (水木 カヤ)
• A famous voice actor and idol who is acquainted with Peek a Boo on account of her diving hobby. She is friends with Azusa and thinks highly of Iori. She is Kōhei's favorite voice actress.

Other characters

• Captain Kudō (工藤会長)
• The Captain of the Tennis Club, "Tinkerbell," and an attractive playboy who was publicly humiliated by Iori and Kōhei due to his mistreatment of Aina.
• Hajime Nojima (野島 元)
• One of Iori's classmates at Izu University. A self-styled playboy who is largely unsuccessful in attracting a lover. Although he tries to be charismatic, it usually comes off as lame.
• Shinichirō Yamamoto (山本 信一郎)
• One of Iori's classmates at Izu University. Incredibly blunt in his desire to find a girlfriend, he is often teased by his friends that he will be a lifelong virgin.
• Kenta Fujiwara (藤原 健太)
• One of Iori's classmates at Izu University. A muscular man, and the most decent and innocent of Iori's friends. He is often portrayed as invisible to other significant characters as a running joke.
• Yū Mitarai (御手洗 優)
• One of Iori's classmates at Izu University. Unlike most of the others, Yu is in a relationship with his childhood friend Rie, which his friends immediately attempt to sabotage once they find out. Through a self-destructive desire to flirt or his friends' machinations, he finds himself beaten up by Rie on multiple occasions.
• Shiori Kitahara (北原 栞)
• Iori's little sister, a third-year middle school student who often walks around in an old-fashioned kimono. She pretends to show affection to Iori while secretly trying to mold him into taking ownership of their family's ryokan so she will not have to, as she seeks to escape the stringent demands placed upon her by her parents. Shiori is unusually cunning and intelligent for her age, able to construct surveillance equipment as well as maintain a facade as an impeccably mannered young girl who dotes on her brother. She later develops genuine respect for Iori, although she still dismisses him as dim-witted and irresponsible.
• Naomi Otoya (乙矢 尚海)
• Iori's co-worker, and a high-school student. He is passionate about diving and is the president of the diving club at his school. He secretly likes Iori.[11]
• Sakurako Busujima (毒島 桜子)
• A student at Oumi Women's University. She is focused on good looks, both for herself and her partners.
• Sayaka Kotegawa (古手川紗耶華)
• Chief (チーフ)
• Maki (マキ)

Manga

Written by Kenji Inoue (manga artist) and illustrated by Kimitake Yoshioka, Grand Blue started in Kodansha's manga magazine Good! Afternoon on April 7, 2014.[12] Kodansha has compiled its chapters into individual volumes. The first volume was released on November 7, 2014. As of April 2026, 26 volumes have been released.

Kodansha USA is publishing the series in both digital and print format,[13][14] with 22 volumes published as of June 24, 2025.

Volumes

Anime

An anime television series adaptation was announced in March 2018.[64] It is produced by Zero-G, directed and written by Shinji Takamatsu, with Takamatsu also handling sound direction, and Hideoki Kusama designing the characters.[65] The series aired from July 14 to September 29, 2018, on the Animeism programming block on MBS, TBS and BS-TBS, as well as AT-X.[66] The opening theme song is "Grand Blue", performed by Shōnan no Kaze, while the ending theme song is "Konpeki no al Fine" (紺碧のアル・フィーネ), performed by Izu no Kaze (a group formed by Yūma Uchida, Ryohei Kimura, Hiroki Yasumoto, and Katsuyuki Konishi).[67] The first season was streamed exclusively on Amazon Prime Video worldwide.[67]

In September 2024, a second season was announced, with Takamatsu returning as director and scriptwriter, and Liber joining Zero-G for animation production.[68][69] The season aired from July 8 to September 23, 2025, on Tokyo MX and other networks. The opening theme song is Seishun Towa (青春永遠), performed by Shōnan no Kaze featuring Atarashii Gakko!,[71] while the ending theme song is "Hadaka de Dotsukiai" (裸でどつきあい), performed by Seamo featuring May'n.[72] Crunchyroll is streaming the second season.[73] Tropics Entertainment licensed the series in Southeast Asia for streaming on Tropics Anime Asia YouTube channel.[74][75]

After the airing of the final episode of the second season, a third season was announced.[76][77] It is set to take place in fictional Palau.[77] The season is produced by Zero-G and Saber Works, with Takamatsu returning as director. It is set to premiere in July 2026.[78]

Film

A live-action film adaptation was announced in November 2019.[79] It was directed by Tsutomu Hanabusa, and originally scheduled to release on May 29, 2020;[6] however, it was postponed to August 7 of that same year, due to the COVID-19 pandemic.[80][81]