Yayoi Hanayama (ハナヤマ・ヤヨイ, Hanayama Yayoi) is a character in Flower, Sun, and Rain. She is described as an "office lady for a leading company" from Japan. She first appears in the second chapter of the game, sunbathing by the pool on the roof of the Flower, Sun, and Rain hotel. Sumio Mondo speaks to her at the request of Stephan Charbonie, after which she becomes attracted to Mondo. Charbonie, obsessed with Hanayama, becomes jealous of this and explains to Mondo his plan to poison and kill Hanayama. Mondo uses Charbonie's hints to search for an antidote but without success. Believing he is too late to save Hanayama, he then realizes Charbonie lied, when in fact the woman was merely drugged unconscious. Hanayama returns in one more chapter, when Mondo pursues a child named Shoutaro Kai. Mondo receives word from Mr. Pirate that Kai was last seen with Hanayama, but he finds no sign of the boy from an investigation of Hanayama's room.
Hanayama alludes to naturally having dated many men. She describes one in particular, a Dutch soccer player who would be upset by the smallest of issues.
- Although she is not a soccer enthusiast, her favorite team is Liverpool.
- Yayoi Hanayama bares resemblance to and shares the given name of Yayoi Itsushima, a character in the video game Moonlight Syndrome. Many fans believe the two to be the same person; as Yayoi got away with her actions in Moonlight Syndrome, she would have a reason to have changed her name.