Mari Tamaki, nicknamed Kimari. A weak-willed girl who struggles to make decisions, she wanted to change her dependent self who relied on her childhood friend Megumi. However, inspired by Shirase's obsession with going to Antarctica, she decides to cooperate to make that journey a reality. She is a bit airheaded and childish, but possesses a pure and straightforward personality. While she lacks a sense of urgency due to her easygoing nature, she empathizes deeply with others, a trait that naturally opens up people's guarded hearts. Her private life is quite messy; she has terrible sleeping posture and her room is always cluttered.

Shirase Kobuchizawa. A girl with an abnormal obsession with going to Antarctica, influenced by her mother Takako, who went missing there. Her nickname at school is "Antarctica," and she is treated as an eccentric. Her passion is genuine—she worked multiple part-time jobs as a high schooler to save one million yen—but she often spins her wheels. She can be strong-willed and bold when her competitive spirit is ignited, but becomes suddenly timid without it. Though she is a cool beauty, she is surprisingly shy, lacks courage at critical moments, and is prone to making major blunders due to her carelessness. She is what one would call a "disappointing beauty" or a klutz.

Hinata Miyake. A girl working at a convenience store near the high school attended by Kimari and Shirase. Due to past experiences (implied to be overhearing gossip), she feels suspicious when others show her concern, making her uncomfortable in large groups. She dropped out of high school after being betrayed by teammates in her club. She is academically capable enough to have passed the High School Equivalency Exam, and she is generally sociable. She became interested after overhearing the two talking, and grew closer to them when Kimari started working at the convenience store, eventually deciding to join Shirase's trip to Antarctica. She is the most reliable member of the group. While she has the best figure among them, she is the shortest, and her looks were harshly criticized by Yuzuki's mother, Tamiko (in the sense that she wasn't at a level to succeed in show business). She has a habit of spouting things that sound like profound quotes.

Yuzuki Shiraishi. An idol talent living in Hokkaido. She was chosen to go to Antarctica as part of her work, but she wasn't very enthusiastic about it. Busy with her career since childhood, she never had the chance to make friends. However, she opens her heart to Kimari's innocence and becomes positive about the trip on the condition that she can bring Shirase and the others along. Although she is the youngest of the four, she watches over the unreliable older girls with a detached perspective, serving as the group's most functional straight man. Having worked from a young age, she is mentally mature and has a wealth of life experience. However, because she lacks experience with peers, she is hungry for friendship. Her catchphrase is "I could just die" or "I'll just die."