| Rin Matsuoka
|Romaji Name||Matsuoka Rin|
|Age||17 years old|
|School Year|| 3rd Year
|Japanese Voice||Mamoru Miyano|
|English Voice|| Vic Mignogna
Rin Matsuoka is a student at Samezuka Academy. He is the freestyle and butterfly swimmer on Samezuka Academy's swim team and a 3rd year high school student. After Seijuro Mikoshiba graduated from Samezuka Academy, Rin became the new captain of the swimming team.
Rin is a good-looking, fairly tall teenager, standing at 177 cm (5 feet, 10 inches) He has red hair and side-bangs, and red eyes. His hair in the CM is styled differently than his hair in the official PV (though this might be because there is a two year gap between the two promos). Rin's teeth are noticeably sharp, which is one of the reasons why he is known as being similar to a 'shark'.
Rin, Haruka, Makoto, and Nagisa were in the same swimming club during elementary school. The group won a relay just before Rin left to go to Australia. The trophy was buried in a time capsule at their swim club. He raced Haruka during a visit in the winter of the first year of middle school and took a devastating loss. He has returned home every New Year, but never made contact with his previous friends.
- Rin's behavior is different in the PV, compared to the CM. This suggests that something happened while he was abroad, something that changed him from an outgoing and cheeky Rin, to a more solemn, and also rather reserved, Rin.
- Fans speculated that he and Nagisa were related because of their similar eye shape and color in the CM.
- Rin has a little sister named Gou Matsuoka who is a first year student at Iwatobi High School. She is the manager of the school's swim team.