Ryunosuke Hanakuma (花隈 竜之介 Hanashima Ryūnosuke) is a 3rd year, class A, and swimming club's vice-president, despite being unable to swim. He acts more like his club's manager.
Ryunosuke is quite the intellectual type who spends most of his time reading while poolside and almost never seen without his handbook. Due to this, he is the one to put some common sense into his club members. However, he is not so stoic as he often goes along with Takato Kiyosu's antics, being the smart and competent one of the duo where he is even giving some snarky remarks every once in a while.
Ryunosuke is the vice president of the Swimming Club. As the calmer one of the two, Ryunosuke is the one who keeps Takato grounded. He is also Takato's current best friend and partner in nanpa. Ryunosuke also enjoys poking fun at Takato about his fear of ghost stories, encouraging others to tell ghost stories or go more in depth about ghosts or other strange beings. He also says that he does nanpa with Takato because it's fun to see if he can still pick up girls while having the disadvantage of Takato being there. Ryunosuke, like Rei, also wants Takato to earn more points for their club.
- Tori Soboro-an
- The name Ryunosuke means "dragon" (竜) (ryu), "this" (之) (no) and "forerunner, herald" (介) (suke).
- Ryunosuke's surname Hanakuma means "flower, blossom" (花) (hana) and "corner, nook, recess" (隈) (kuma).