Mai Sunagawa is a character from the beach volleyball anime Harukana Receive. She is a student who forms a beach volleyball pair with her upperclassman, Ai Tanahara. Mai is characterized by having a complex about her own height, which is a significant part of her personal background and motivation within the story. This insecurity is a shared trait with one of the main protagonists, Kanata Higa, who also struggles with being shorter than many of her opponents in a sport that often favors taller athletes.

Her personality is initially revealed through her interactions with Ai. It was Ai who recruited Mai to play beach volleyball, using the convincing argument that it is a sport where shorter players can defeat taller ones. This suggests that Mai may have been hesitant or lacked confidence before being encouraged by her partner. On the court, she plays as a libero, a defensive specialist position that is typically filled by one of the shortest members of a team. This role suits her physicality and allows her to leverage her skills defensively.

In the narrative, Mai and Ai serve as opponents for the main duo, Haruka and Kanata, during their first official tournament match. Their presence in the story highlights a key theme of the series: overcoming physical disadvantages through strategy and teamwork. During their match, it is noted that Kanata strategically targets Mai, not out of malice, but because it is a logical tactic, a strategy that Kanata herself has often faced due to her own lack of height. This creates a parallel between the opposing pairs and adds a layer of empathy to their competition.

Her most significant relationship is undoubtedly with her partner, Ai Tanahara. Ai serves as her motivator and the more assertive half of their pair. The two are seen buying matching swimsuits, a significant act in the series that symbolizes the bond and commitment between beach volleyball partners. By the time of the Okinawa qualifiers, circumstances have changed, as Ai has graduated from high school, and Mai is no longer competing with her but is instead seen watching the tournament. This development shows the natural conclusion of a high school sports partnership due to graduation. Her notable ability is her skill in her specialized position as a libero, focusing on defense and receiving the ball. While a minor character, Mai Sunagawa represents the personal struggles and partnerships that exist beyond the main cast, reinforcing the series' central themes of overcoming self-doubt and the value of a supportive teammate.