Rin Matsuoka/Relationships

Relationships
Samezuka Academy=

Having heard of Rin's success and hard work from Seijuro, Aiichirou highly looks up to Rin as a mentor and role model. He regularly accompanies Rin while he trains  and enthusiastically helps him in any way he can. Initially, Aiichirou and Rin were not on the same team, however, once Rin joined the Samezuka Academy swim team, the two became teammates. Rin also finds Aiichiro to be a bit overwhelming and overbearing, especially so if he had been a girl and had to date him or Seijuro. Up until the final episode, Rin refers to Aiichiro by his last name, Nitori, but following his endeavor with the Iwatobi Swim Team he off and on calls him "Ai" for short. In return, Aiichiro happily addresses Rin as "Rin-senpai."

Sosuke joined Sano SC in the third grade of elementary school when Rin was already a member and could swim butterfly. Rin forced Sosuke to join and learn swimming butterfly too and Sosuke would always be left saying "Ugh, just shut up". Since Rin was faster and wasn't saying anything wrong or untrue, Sosuke let him trying to teach him butterfly, even though it greatly pissed him off. Their relationship kept being like that for over a year up until Sosuke became a good match for Rin. Because Rin was the one who taught Sosuke how to swim, things like the timing of their breaths or the way they moved their arms were exactly alike and, as Sosuke once stated, he couldn't seem to shake it, it was just ingrained then. During the time he was at Sano SC, Sosuke and Rin's relation was having competed for being the representative, formerly they certainly had a relationship that could be called friends.

When Rin said that he wanted to go Australia and when he said that he wanted to swim at Iwatobi SC, just saying ‘I understand’ while he was half shocked, he didn’t try anything like halfheartedly keeping him back or pressing questions. Sosuke kept being someone who understood Rin well until the end.

In High☆Speed!, Rin stated that it’s better if he's not on the same team as Sosuke because they "understand each other too well". He says that Sosuke’s even more theoretical than he is and that they often quarreled. They settled on it that the faster way is always correct, but their competitive spirit wasn’t half-baked anymore. He said that he doesn't hate him. Rather, he still thinks of him as the person who understands him the most, but sometimes it becomes difficult to be together. When he ends up understanding Sosuke's feelings, he ends up not being able to say the things that he wants to. He could no longer seriously go up against Sosuke. because he was that one friend who got him way more than his other friends, and that made Rin feel uncomfortable. He said that that was not a friend, but like an alter-ego (you don’t like or hate your alter-ego).

Even though Sosuke and Rin didn't see each other in such a long time, they're still great friends. Sosuke likes teasing Rin, as seen when Rin asked him if he's going to stop swimming and has a special type of a handshake with him. Sosuke is very concerned about Rin and his future and greatly dislikes everybody who stands in Rin's way to success, including Haruka, who, according to Sosuke, did "something Sosuke would never do".

Initially, Seijuro and Rin did not know each other at the beginning of the series despite attending the same academy because Rin did not join the swim team at first. However, once Rin joined the Samezuka Academy swim team, the two became teammates and, so to speak, friends.

Despite being Rin's senior and captain, Rin does not like Seijuro at all, often addressing him simply as "Mikoshiba" when he's not around. However, the moment Seijuro appears, Rin addresses him politely as "Captain". in does not see Seijuro to be very responsible and finds that he is a bit too whimsical. However, he still respects him as his captain and fellow teammate. Rin does not tolerate Seijuro's attempts to go on a date with his sister and often stands in his way, being an over-protective brother he is. He also sometimes gets "an overwhelming urge to punch Captain to the ground" when Seijuro and Gou talk.

Iwatobi High School=

Gou is often worried about her brother. One of her main reasons in becoming Iwatobi's swim manager is that the guys will help bring her brother back to normal. Rin in response appears a bit protective of her as well especially in response to Seijuro's use of Gou's first name and his attempts to go out with her, which are often ruined by Rin personally.

In the drama CD, Rin was curious about Gou going out every Sunday, and thought that she went on dates with Seijuro. He even called Makoto and asked him what are they doing on Sunday. After Rin and Nitori stalked Gou, they were surprised that Gou was actually being helped by Hanamura to buy Rin a Christmas present, and that she wrote on the card "Thank you for everything, onii-chan". Hanamura said that she's jealous of Gou to have such a good-looking brother, but Gou admitted that he can be a pain sometimes and that he's never honest with his feelings.

In elementary school, Rin was in the same swimming team as Haruka, Makoto and Nagisa. After they won a tournament, Rin went abroad to Australia to study swimming. Haruka constantly remembered how Rin promised him to show him a sight he has never seen before, and held onto that memory. When Rin made a rare return to Japan, Haruka and Rin raced, and the former easily won. Rin was exceptionally disappointed that his hard work was for nothing; this created a rift between them, as Rin refused to take Haruka's extended hand. Subsequently, Haruka gave up competitive swimming because he damaged Rin's pride. Later, when they went against one another again, and Rin won without much difficulty, Rin was not satisfied as Haruka was not swimming at his best potential. He urged Haruka to swim competitively, so that they may have a fair race, to which Haruka complied.

Rin's best stroke is the butterfly, but his obsession with beating Haruka, who only swims the crawl stroke, led him to focusing on that stroke and whatever distance Haruka was swimming in the competitions only.

Throughout their various encounters, their relationship was portrayed to be very tense, as Rin was continually preoccupied with the notion of beating Haruka. Rin sometimes got very frustrated with Haruka, acknowledging that Haruka has the ability to showcase that he is an extraordinary and unusually excellent swimmer, and yet Haruka only cared about immersing himself in water. When Rin officially defeated Haruka at the prefectural tournament, Rin claimed that he will now never swim with Haruka again, resulting in Haruka's utter despair. For Haruka, it was not all about winning. Makoto later told Rin that Haruka had thought something else mattered more, which was why Haruka wanted to race with Rin. Nevertheless, Rin did not understand him.

In the final episode of the anime, when Haruka saw that Rin was struggling in his individual race, of which he consequently lost, he immediately rushed from the stadium to go look for Rin, prompting the others to follow. They overheard that Rin was taken out of the relay and wanted to quit swimming for good; this instantly had a destructive toll on Haruka, who faltered and buried his face in his arms. Haruka longed desperately to swim with Rin again. When Rei assured Haruka that Rin was not particularly angry with him but was emotionally scarred by his own failures and insecurities in Australia, and that his true desire was to swim with everyone again, Haruka was determined to find Rin. Haruka ended up being the first to locate him, having correctly inferred that Rin would be at the tree that looked similar to the one in the Iwatobi Elementary School yard. When Rin took notice of him, he started to lose his sanity because he was not able to swim with Haruka again. He aimed to punch Haruka, but Haruka stopped him, making them both fall and roll on the ground. When Rin saw what Haruka wrote on the ground before the tournament—he wrote "For the team," a phrase Rin had written in their childhood—he started crying, asking him why could not swim with them again. Haruka reassured him that he still could, and told him that it was his turn to show Rin a sight he has never seen before.

At the relay race at the tournament, Rin, at last, got to participate in the relay with his old team again. Rin swam right before Haruka, and when it was Haruka's turn, Rin was captivated. They managed to win, and Rin ran to Haruka, hugged him and cried that it was, indeed, the best sight he could have ever asked for. In the credits, it was shown that Haruka and Rin became great friends once again, as they began to divulge their respective dreams and goals to one another.

When Rin first transferred to Iwatobi elementary, Makoto was much more open and kind to Rin than Haruka; who (at first) didn't want to get involved. Makoto wanted to swim in the relay with Rin, and was able to convince Haru to swim with them as well. During their time in elementary school, Makoto and Rin were close friends; Both being friendly and outgoing. When Rin returned to Japan, he barely paid attention to Makoto or Nagisa, asking "You're still hanging out with these guys Haru?". When Rin beat Haru at regonials, the boys went looking for Haruka after he failed to return. They bumped into Rin, who thought that Haruka was upset due to loosing to Rin. Makoto responded sternly by saying that swimming meant something more to Haru, and he's pretty sure that Rin was the one who taught him was it was. In the last episode Rin appears to have rekindled his friendship with his old friends.

Others=

Unlike Makoto and Nagisa, Rin calls Aki the more formal "Yazaki-san." In High Speed!, Rin thinks Aki is someone who can influence Haruka's way of thinking, and although he later feels bad for asking that Aki prompt Haru to join the medley because of this, he's reassured that it wasn't offensive, because much like him, she wants to see Haru join the medley too. They have a mutual respect for each other, connecting through their conversation about Haru, and are even able to joke around together.

In Aki's POV, she's shown to wonder over how he's always "running towards somewhere," seeking something.