Mina and Tsuyu are both students in U.A. High School's Class 1-A. The two seem to have grown close over the course of the series due Mina being seated in front of Tsuyu in class, and often hang out together. When they and the rest of some of their classmates congratulate Izuku Midoriya when the battle test ended, Tsuyu was behind Mina when she introduced herself to Midoriya and Mina did not seem bothered by his presence, showing that from the beginning they both girls got along well.
During the sports festival, Mina and Ochako Uraraka is impressed by how fast Tsuyu can move across a length of rope stretched over a chasm and after the cavalry battle, when Mina moves on to the final round, Tsuyu he approaches her to congratulate her enthusiastically, despite being upset that she couldn't move on. When Mina has her first one-on-one battle against Yuga Aoyama, Tsuyu eagerly cheers her on from the stands, and is happy that she wins.
Two days after the Sports Festival, Mina talks to Tsuyu and Kyoka Jiro about her training at a workplace to work and after they all return from their internships, Tsuyu tells to Mina and the other girls about her experience stopping drug smugglers with the Oki Mariner crew, which Mina finds extremely cool. The two also get together to go to a hotel with Toru Hagakure on I-Island, while the other three girls see the Expo preview. Although Mina was initially upset about not being able to go, she seems to have a good time with Tsuyu and when the island goes into alert mode, Mina is worried and Tsuyu tells her that as long as they follow the rules they will be fine, making Mina smile at her calmly.
When Mina discovers that Ochako has a crush on someone shortly after "super move training" for the Provisional License Exam, Tsuyu stops her along with Momo Yaoyorozu and they tell Mina to stop meddling in Ochako's love life. During and after Director Nezu's speech, Mina talks and whispers quietly with Tsuyu and also congratulates her and Ochako after they make their debut as Heroines, fighting two villains with Nejire Hadou and Ryukyu. When Tsuyu participates in the raid against Shie Hassaikai, Mina is worried about her and was thrilled and relieved when Tsuyu and the other students involved returned to the Academy, bringing Koji Koda's bunny to Tsuyu and Ochako to help them cheer up.
For the school festival, Mina decides to choreograph a dance for part of the concert Class 1-A will put on and Tsuyu happily becomes part of the dance team, and learns and works on the dance with Mina and the others. After the people of Nabu Island are evacuated to a hideout by the threat posed by Nine and his team, Mina and Tsuyu are in the kitchen cooking with Koji. When winter break is over and students return from their Work-Studies to show their progress with their Quirks and skills, Mina and Tsuyu are the first to leave the homeroom and greet their teacher, Shota Aizawa, and in the demonstration they both see Ochako and Midoriya's the union of fists happily.
MinaTsuyu is a relatively rare pair rivalled mostly by TsuChako, TokoTsuyu, MinaOcha, and KiriMina, the most popular het ships for Mina and Tsuyu and the more popular femslash ships for both girls. However, many people enjoy the two as a pairing due to their close friendship and somewhat contrasting personalities-Tsuyu being more calm and collected, and Mina being loud and at times overzealous. Fans also enjoy the pleasing nature of their color motifs, pink for Mina and green for Tsuyu, and think they fit well together. People also suspect that Tsuyu and even Mina may be interested in girls, due to how touchy they are with each other and certain other girls in their class, and Tsuyu's lack of interest in boys.
A popular thing noticed between fans are their less than human features, making for a rather interesting looking couple!