|Age|| 14-15 (High☆Speed!)
19-20 (Free! Take your marks!)
|Height|| 168 cm (5'6") (High☆Speed!)
185 cm (6'1") (Free! Take you marks!)
|Occupation|| Team сaptain (former)|
|Affiliation|| Iwatobi Junior High School (former)|
Iwatobi Swimming Club (former)
|Relatives|| Ikuya Kirishima (younger brother)
|Anime||High☆Speed！－Free! Starting Days－|
|Light Novel||Volume 2|
Natsuya Kirishima (桐嶋 夏也 Kirishima Natsuya) is a junior high student who debuted in the second volume of the light novel High☆Speed! written by Kōji Ōji. He is a minor character in High☆Speed！－Free! Starting Days－, Free! -Take Your Marks- and Free!-Dive to the Future-. He is the older brother of Ikuya Kirishima.
Natsuya is a relatively tall and muscular young man with short, unruly brown hair and amber eyes.
Natsuya is a boisterous, keen, and upbeat character. On the surface, he doesn't seem deterred by much but shows a vulnerable side to his friend Nao Serizawa after feuding with his younger brother. He is angered easily by Haruka Nanase's apparent disobedience and impassivity. He is kind and firm, aspects shown often around his team.
Kirishima Natsuya was the captain of Iwatobi Swimming Club in Iwatobi Junior High School. His little brother, Ikuya Kirishima, also participated in his team. One of his closest friends was Nao, the team manager. He ended up recruiting Haruka Nanase, Makoto Tachibana, Asahi Shiina and his younger brother for the team shortly after they began their first year of middle school. The movie and light novel ends with him still holding his title as the captain of the team.
- Main article: Natsuya Kirishima/Plot
He appears to have a good relationship with Nao. The tension between him and Ikuya eases up toward the end of the light novel. Although his little brother is already an adult, Natsuya still treat him just like a little kid, it was shown in Free! Take your marks! that Natsuya still cannot believe that Ikuya's not the same person who he knew in the past and said that he missed the past Ikuya. He seems easily agitated by insolence, as shown by the younger members of the team when they were not cooperating with each other.
- Main article: Natsuya Kirishima/Relationships
- Natsuya's least favorite subject is Math.
- His motif animal is a tiger shark.
- He hates shiitake mushrooms but will eat them when he is with Ikuya to set a good example
- His favourite quote is said by Mihail which is “Victory only comes to those who believe in themselves,” which he interprets as ‘the results depend on you.’