Akito Sorami
The sole member of Hoshino Dai-ichi High School's Astronomy Club who infamously doesn't even look at the stars.
- Affectionate Nickname: Saya calls him "Akkun," while Korona calls him "Akky."
- Childhood Friend Romance: He can get together with Hikari and/or Saya, his friends from elementary school.
- Innocently Insensitive: Upon first seeing Saya's mismatched eyes, he compares them to the Binary Star Albireo. Not knowing that Albireo is the name of a star, Saya believes he has called her a monster and starts to cry.
Hikari Houkiboshi
- Voiced by: Jun Miruno
Akito's friend from elementary school who suddenly moved away before the school closed down, only to make a surprise return in high school.
- Childhood Friend Romance: She quickly became friends with Akito during elementary school, and can potentially get together with him in high school.
- Embarrassing Nickname: She doesn't approve of Korona referring to her as "Pikarin."
- Hidden Buxom: While her winter jacket might make her look modestly-endowed at best, her other outfits make it obvious that she's stacked; at 91 cm, she's second only to Orihime in terms of chest size.
- I Want My Beloved to Be Happy: In her route, she tries to reject Akito and push him towards Saya in spite of her own feelings towards him. This is Played for Drama, as her persistence in this absolutely infuriates Saya, who does not want to be second choice and of course also wants her childhood friends Akito and Hikari to be happy.
- The Matchmaker: Tried to play matchmaker for Akito and Saya in their childhood days, before developing feelings for him. During the game, she offers to play Cupid for Takeichi and Narue.
- Tomboy and Girly Girl: The Tomboy to Saya's Girly Girl.
Saya Amanogawa
- Voiced by: Ai Matayoshi
Akito's friend since elementary and a student at Seisen Academy who regularly comes to Hoshino Dai-ichi to give him food while he stays in his clubroom.
- Childhood Friend Romance: She's in love with Akito, who she's been friends with since elementary school.
- Shrinking Violet: She's been incredibly shy since she was a kid.
- Tomboy and Girly Girl: The Girly Girl to Hikari's Tomboy.
Orihime Shiratori
- Voiced by: Tae Okajima
The playful president of Meikou Academy's astronomy club with an interest in tarot cards. She convinces Akito to take part in the Mutsuraboshi Conference.
Korona Kusakabe
- Voiced by: Natsumi Takamori
A girl one year younger than Akito, who she's incredible fond of. She intends on attending Meikou Academy.
- Genki Girl: She's incredibly energetic, and has been since childhood.
Takeichi Kusakabe
- Voiced by: Junji Majima
Korona's older brother and a friend of Akito who's part of the basketball club at Hoshino Dai-ichi.
- Affectionate Nickname: Saya calls him "Take-kun," as does Narue.
- Official Couple: He gets together with Narue.
- Reformed Bully: He was a jerk towards Akito and Saya during elementary school, but mellowed out and become friends with them by the time they entered high school.
- Took a Level in Kindness: He went from a bratty kid to a pretty mellow teen.
Miharu Saotome
- Voiced by: Saki Nakajima
Akito's former elementary school teacher who has since shut herself in her parents' home after the school was closed.
- Broken Pedestal: Hikari used to look up to her back in elementary school, but that perfect image was destroyed upon seeing how what kind of lifestyle she's been living since said school was closed.
- NEET: Ever since she stopped teaching, she's just been lazing around her parent's house. It's gotten to the point that her mother openly wants her to get married to Akito (who works at their convience store) so he can take care of her.
- Promoted to Love Interest: She gets her own route in FINE DAYS.
- Teacher/Student Romance: FINE DAYS allows her to get together with Akito, who used to be her student.
Honoka Yoshioka
- Voiced by: Sayaka Matsuyama
A first-year at Meikou Academy who takes over as president of the Astronomy Club after Orihime graduates.
- Not So Above It All: While she normally comes across as very mature compared to the more eccentric Orihime, there are times where she joins in on her upperclassman's antics.
- Promoted to Love Interest: She gets her own route in FINE DAYS.
Hinami Yamada
- Voiced by: Haruna Iwasaki
A friend of Korona's who is one year younger than Akito, she becomes the only other member of Hoshino Dai-ichi's Astronomy Club following the end of the common route.
- Bunny-Ears Lawyer: Has shades of this, being very quick to learn the ropes at Akito's job as well as how helpful she is during various Six Stars Club events.
- Cloudcuckoolander: Has a very interesting obsession with black holes, claiming Saya is the "Albeiro Princess" (and getting awkwardly shy around her), throwing in odd astronomy-like terms during conversations, and many characters are quoted to "not knowing what she's thinking".
- Loon with a Heart of Gold: She's quirky and blunt, but a very nice and sweet girl once you get to know her. Shown in FINE DAYS when she volunteers to be Akito's replacement at his job since she knew he was graduating.
- Promoted to Love Interest: She gets her own route in FINE DAYS.
Tamaki Koganei
- Voiced by: Rie Okamoto
A first-year at Seisen Academy.
Narue Jinno
- Voiced by: Kei Mizusawa
The president of the Earth Science Club at Amenonakanishi High School.
- Official Couple: She gets together with Takeichi.
- Mistaken for Romance: Takeichi was initially dejected when it looked like she was going to out with Toyoda, but was relieved to find out he was just reading into things too much.
Toyoda
- Voiced by: Keisuke Nakamura
A quiet boy in Amenonakanishi's Earth Science Club who takes over as president after Narue graduates.
- Only One Name: His first name is never mentioned.
Noriko Kanou
- Voiced by: Hitomi Takeuchi
The president of the Tennochu Academy's Astronomy Club, though she hasn't made any observations in the field before the events of the game.
Keisuke Tajiri
- Voiced by: Yuuichi Masuda
The Astronomy Club president at Morumisawa Boys Academy.
Kawanakajima
- Voiced by: Akito Sakuragi
A member of Morumisawa's Astronomy club who takes over as president after Tajiri graduates.
- Only One Name: Like Toyoda, his first name is never given.
Ichiro Morita
- Voiced by: Tōru Ōkawa
The director of the resident planetarium.
Kotarou
- Voiced by: Tomoe Jinbo
A normally timid Shiba Inu under the ownership of the Saotome family.
- Affectionate Nickname: Saya refers to him as "Kotie."note
