Sosuke Yamazaki/Relationships

Samezuka Academy=

Sosuke joins the Sano Swimming Club in the third grade of elementary school when Rin Matsuoka is already a member and can swim butterfly. Rin forces Sosuke to join and learn swimming butterfly, too, and Sosuke is always left saying, "Ugh, just shut up." Since Rin is faster and doesn't say anything wrong or untrue, Sosuke allows him teach him butterfly, even though it annoys him. Their relationship continues like this for over a year until Sosuke becomes a good match for Rin. Because Rin is the one who teaches Sosuke how to swim, things like the timing of their breaths or the way they move their arms are exactly alike and, as Sosuke once states, he couldn't seem to shake it, it was just ingrained then. During the time he is at Sano SC, Sosuke and Rin compete for the role of representative, but they are certainly friends.

When Rin says he wants to go Australia and when he says that he wants to swim at the Iwatobi Swimming Club, Sosuke responds ‘I understand’ and while he is surprised, he doesn't attempt to keep him back or press Rin with questions. He just keeps being someone who understands Rin well until the end.

In High☆Speed！, Rin states that it's better if he's not on the same team as Sosuke because they "understand each other too well." He adds that Sosuke's even more theoretical than he is and they often quarrel. They settle it by agreeing that the faster way is always correct and that their competitive spirit is no longer half-baked. He says he doesn't hate him; rather, he thinks of him as the person who understands him most, making it 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. He can no longer seriously go up against Sosuke because he is that one friend who gets him way more than his other friends and that makes Rin feel uncomfortable. He says that Sosuke is like an alter-ego (you don’t like or hate your alter-ego).

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

Aiichiro Nitori greatly admires Sosuke, be it because he is a high class swimmer (being in the top ten butterfly swimmers), or because of his long relationship with Rin. At first, Sosuke seems to dislike Aiichiro, giving him a cold look when he tries to approach him, but then he quickly smiles and ever since then, they're on good terms. While Aiichiro works solo to gain a place in regionals, Sosuke offers to train him. Alongside Rin and Momotaro Mikoshiba, Sosuke and Aiichiro compete against Team Dolphin, losing at the end.

Sosuke and Momotaro have a friendly relationship due to them being former teammates while Sosuke attends Samezuka Academy. Iwatobi High School=

Sosuke initially does not like Haruka and thinks he gets in Rin's way. He confronts him in the second episode of Free!-Eternal Summer- to tell him this. However, as the season progresses, Sosuke starts to understand Rin and Haruka's rivalry as positive, and although he still doesn't accept Haruka, he wants Haruka to do his best so Rin can also do his best. In Forbidden All-Hard!, Sosuke and Haruka are put on the same survival team, much to their dismay. They both feel awkward, but bond when Haruka gives Sosuke a water gun when his runs out of water, and later, when Sosuke steps in front of Haruka in order to "save" him from Rin's shot--thus keeping Haruka in the game and taking Sosuke out of it. After this OVA, they are shown finally making peace with each other and getting along.

Sosuke and Makoto Tachibana are shown to be friendly with each other as seen in the Forbidden All-Hard! when Sosuke tells Makoto to call him by his first name. They also are close enough to share phone numbers, as seen in episode 3 of Free!-Dive to the Future-, where they are seen talking about swimming and various competitions.

They are shown to be on good terms. In season 3, Iwatobi and Samezuka have joint practices, so Sosuke can be seen hanging around with the Iwatobi boys due to him being there to support his former teammates at Samezuka.

They are shown to be on good terms. In season 3, Iwatobi and Samezuka have joint practices, so Sosuke can be seen hanging around with the Iwatobi boys due to him being there to support his former teammates at Samezuka.

Due to being best friends with Rin and hanging out when they were younger, Sosuke has hung around Gou Matsuoka a lot, too. They are shown having a good relationship and Sosuke is quite protective over her, as seen in Forbidden All-Hard! when Aiichiro Nitori accidentally sprays water on Gou while she's not wearing a jacket, thus making her cold. Sosuke takes revenge by dousing him with his water gun and giving Gou his own jacket to wear.