TV-Series
Description
Mina Yayoi, a first-year student in Class 1-C at Tsugumugino High School, possesses waist-length cerulean hair often styled in two ponytails or worn straight, complemented by burgundy eyes. Standing 148 cm tall and weighing 39 kg, her birthday falls on March 11 and she has AB blood type. She wears the standard female school uniform.

Inherently shy, timid, and lacking self-confidence, Mina grapples with social interactions and actively avoids attention. This discomfort persists even when recognition comes from her achievements as a backstroke specialist on the school swimming team. Dolphins captivate her; she admires their grace, collects dolphin memorabilia, and dreams of swimming alongside them in the ocean—a childhood aspiration. Her passion for marine life leads her to avoid preparing seafood. Despite her reserved demeanor, she commutes by bicycle, reflecting athleticism. Her closest friend is Momo Aikawa.

Mina first encounters Riku Aoba in the school library where he helps her reach a high-shelved dolphin book; she doesn't introduce herself. Their second meeting occurs near her bicycle. After he sneezes, she offers her handkerchief, nervously reveals she knows his name, then hastily departs. Later, seeking improved mental focus for competitions, Mina asks Riku to coach her swimming, developing unspoken romantic feelings she struggles to confess due to shyness.

Disappointed at failing to spend time with Riku during the Cultural Festival, Mina attempts mobile contact when he leaves for a school trip. His neglect in checking messages causes escalating distress. Her anxiety peaks during an emotional breakdown at an aquarium; dolphins gather near her as she cries. Discovering her numerous messages and a voicemail expressing loneliness and a desire to see him upon his return, Riku apologizes with a dolphin pendant keychain, which she accepts happily. She visits his home on New Year's Day alongside Sayuri Amamiya and Tsukasa Kasuga. Learning of Riku's impending school transfer on Valentine's Day, Mina confesses her feelings at a shrine and receives his response.

Through swimming and her interactions with Riku, Mina gradually cultivates resilience and determination. Her self-confidence strengthens, leading to greater openness with others. Koayu Utsumi, the swimming team captain, mentors her as an upperclassman. Her name's etymology reflects her traits: "Mina" combines "water" (水) and "apple tree" (奈), while "Yayoi" means "spring" (弥生).