|Also known as||Iku-Chan (by Nagisa Hazuki)|
|Age|| 12-13 (High☆Speed! Vol. 2)|
17-18 (Free!-Take Your Marks-)
|Height|| 143 cm (4'8") (High☆Speed!)|
173 cm (5'8") (Free!-Take Your Marks-)
|Education|| Shimogami University|
|Clubs|| Shimogami University Swim Club|
|Swim Style|| Breaststroke (specialty)|
|Events|| 4×100 m medley relay|
400 Individual medley
Natsuya Kirishima (older brother)
|Anime|| High☆Speed！－Free! Starting Days－(movie)|
Episode 26 (anime)
|Light Novel||Volume 2|
|Japanese|| Koki Uchiyama|
|English|| Lee George|
Dani Chambers (child)
Ikuya Kirishima (桐嶋 郁弥 Kirishima Ikuya) is one of the main characters in the movie High☆Speed！－Free! Starting Days－ and Free!'s third season, Free!-Dive to the Future-, as well as a minor character in the light novel High☆Speed！. He is the younger brother of the Iwatobi Junior High swimming club's captain, Natsuya Kirishima. He is currently studying at Shimogami University, where he is on the swim team alongside his friend from America, Hiyori Tono. As of Free! 2021 Gekijou-ban he appears to be a swimmer for the Japanese Olympic Team.
Ikuya is a muscular, though smaller-framed young man with deep teal hair, vermilion eyes and long, black eyelashes. He and his brother do not look particularly alike, but share the same eye color. In competition, he wears black jammers with subtle brown and gray designs.
When first introduced to the series as a member of the Iwatobi Middle School Swim Club, Ikuya is quiet, cynical, and distrustful of others. Though taciturn, he isn't afraid to express his annoyance or to speak his mind and was at odds with his older brother, Natsuya. When Natsuya, as swim club captain, tries to enlist new members for the swim club, Ikuya resists, saying school-based sport clubs are a waste of time. Though he eventually joins, it takes time for him to warm up to his teammates - Haruka Nanase, Makoto Tachibana and Asahi Shiina - but comes to trust them. He admires Haruka a great deal, secretly wishing he possessed similar confidence in sport.
Ikuya's health is fragile, and he has some fear of water due to the fact that he nearly drowns several times. Yet, being a determined athlete and not wishing to disappoint Natsuya, he pushes himself endlessly, often suffering from oxygen deprivation from over-training in the pool. This drive is due to his belief that swimming and competition are to be mastered, as indicated by the anime's depiction of water being an "enemy" that binds him. In this way, he is shown to be both similar to and different from Haruka - both brilliant swimmers with radically different approaches to their sport.
Another major difference between Ikuya and Haruka is Ikuya's desire to "never be ordinary." He professes this to his friend, Hiyori Tono, who supports him in this belief but who, unbeknownst to the others, is left in charge of keeping Ikuya's health intact while Natsuya travels the world as a professional swim competitor. This responsibility strains their friendship, but Ikuya remains oblivious to Hiyori's struggle until he is forced to face his past. In making amends with his former teammates and after swimming an IM with Haruka in fulfilment of a promise made long ago, Ikuya feels re-connected to humanity and is also able to reconcile with Natsuya and Hiyori. Only then, does he begin to see himself in a fully "humanized" way, although he still holds competition and winning to be a major goal in life.
Ikuya enjoys swimming as a child, but grows disenchanted with it as he grows older. This is due, in part, to his idolization of his older brother upon whom he depends a great deal. In a misguided effort to force Ikuya to become self-sufficient and independent, Natsuya pulls away emotionally, but keeps pressure on Ikuya regarding sport. Instead of Ikuya rising to the challenge, his fragile self-esteem perceives the distancing as a rejection, and he begins to renounce the things that Natsuya and he used to share, like swimming. In junior high, he tries to avoid joining the swimming club because Natsuya is Captain, but is "roped into" doing so by Haruka, Makoto and Asahi.
Once a member, it becomes obvious that Ikuya is an excellent swimmer, but has health issues due to his perfectionism and over-training to the point of oxygen deprivation. In the past, he had to be hospitalized and as a team member has to be resuced by Haruka. Over time, Ikuya comes to respect and enjoy the camaraderie of being on a team and hopes his newfound friends will continue swimming. Unfortunately, it's at this time that Haruka has a falling out with Rin and gives up competitive swimming. The team's plans to work together fall apart, as do their developing bonds.
Shortly thereafter, Ikuya follows Natsuya to America where Ikuya attends junior high school and meets Hiyori Tono. Upon returning to Japan for high school, Ikuya joins the swim club and continues into college. Through intermittent contact with his former junior high friends and teammates, he makes amends with them and others, including his brother and Hiyori.
- Main article: Ikuya Kirishima/Story
- Main article: Ikuya Kirishima/Relationships
- He's a childhood friend of Satomi Nii, who only appears in the light novel.
- Squirrels are his favorite animals. The reason is "for the tenderness", though he won't admit it.
- His favorite foods are fried shrimp, sweet tamagoyaki, and pistachio cream.
- As the youngest in his family, he has always wanted a younger brother.
- The Little Mermaid book was bought by his father abroad and, for Ikuya, a treasured item associated with him.
- According to Hiyori, pistachio drinks are Ikuya's favorite.
- His motif animal is a beluga whale.
- Ikuya acquired his copy of The Little Mermaid in America. It was a gift from his father, and he treasures it. When he arrived in America' he couldn't read English well, so he would focus on the pretty pictures.