Makoto picks Haru and Rin up at the airport, being like his usual self. They travel to the venue for the nationals. Rin departs to meet up with his team and Haru thanks him. Nagisa and Rei welcome Haru back to Japan. Haru announces that he has something to tell the team. He explains that the reason he never cared about winning or his timing is because if he worries about these, his swimming would have lost its meaning. Previously, he wasn’t able to respond to their concern because Haru did not believe that he can find his dream just by looking. However, after travelling with Rin to Australia, he realises how big the world really is and found his dream there, wanting to enter the world of competitive swimming. For the sake of his dream, Haru is going to start caring about timings. The others are glad that Haru is able to sort out his thinking and has found his dream, saying that they will support him.
While watching others swim, Haru apologies for their confrontation at the festival. However, Makoto says that he is the one who should be sorry because he could not tell Haru about his future plans. He felt that he is not suited for competitive swimming. After helping Goro out at Iwatobi Swimming Club, Makoto realises that he wants to be a coach, showing other kids how fun it is to swim. He is going to a university in Tokyo to achieve this.
After dinner, the team reminisces about their time in the swimming club, thinking all the way back to how the club started, recruiting Rei, Nagisa juggling both his studies as well as swimming and Rei learning all the different strokes. In the moment, Rei lets it slip that he had help from Rin and he finds out that the team already knew. They talk about their first relay, and how hard they have trained for tomorrow. Excitedly, Nagisa declares that they will proceed even further and be more amazing next year. However, Rei reminds him that after tomorrow, the third years are going to be retiring. It is not going to be the four of them anymore. As his words sink in, Rei starts crying, surprising Makoto and Haru. Nagisa starts crying too, saying that he wants the four of them to keep swimming together. As the two continue bawling, Makoto comforts them, saying that they are swimming together tomorrow. Haru agrees, stating that swimming the relay connects them. Even if they end up separating, they are still connected.
The next day, their relay starts. Iwatobi wins their heat, and everyone is overjoyed at the completion of the relay.
At Samezuka Academy, there is the traditional farewell sent off for the graduating third years. Debriefing his team, Rin appoints Nitori as the next captain. Afterwards, Sosuke Yamazaki stares at the pool alone. While leaving, he sees Rin standing at the door. Rin tells Sosuke not to crush his potential before he even tries and says that he will be waiting for him to come back to the swimming world. Sosuke comments that it is exactly what Rin would say, referring to the time where he encouraged Nitori.
The team heads to Iwatobi Swimming Club, burying a time capsule containing the sights that they saw during the nationals. They then head to Samezuka Academy, where a pool filled with cherry blossom is waiting for them.
Makoto is studying hard while Haru is training under a coach in Tokyo. There are plenty of members joining swimming club, delighting Nagisa and Rei. Nagisa is keeping up his efforts to manage his time between his studies and swimming. Hayato is still continuing his swimming lessons at Goro’s place, where it is revealed that the team placed 6th during the national tournament.
At a competition, Rin and Haru are once again in adjoining lanes, facing off against each other.