Born: September 7, 2006 (19 years old), Godeok-dong, Gangdong-gu, Seoul Nationality: South Korea Physical: 168–169cm | Type A Family: Father, Mother, Older brother (born 2004), Dog (Kong-i) Agency: SM Entertainment Group: Hearts2Hearts Position: Leader, Dancer Character: Jju-jebi Debut: February 24, 2025, Hearts2Hearts MBTI: ISTJ Motto: Patience is bitter, but its fruit is sweet. Nicknames: My-Jju, Jju, The girl with short hair, Short-hair sunbae, Human Naevis, Fingers, Choi Leader, Cherry, Ju, White Weasel, Jju-jjon-ku, Girl from a manhwa.

Born: March 28, 2006 (20 years old), Bali Nationality: Indonesia Physical: 168cm | Type O Family: Grandfather, Father, Mother (born 1970), Older sister (born 2000), Older brother (born 2003), Younger brother (born 2007) Agency: SM Entertainment Group: Hearts2Hearts Position: Main Vocalist Character: Bing-ping Debut: February 24, 2025, Hearts2Hearts MBTI: ESFP Motto: Life doesn't always go the way you want. Nicknames: Bali Girl, Carmen-ka, Rumen.

Born: April 12, 2007 (19 years old), Bangok-dong, Wonju-si, Gangwon-do Nationality: South Korea Physical: 164cm | Type B Family: Parents, Twin younger sister, Younger sister (born 2013) Agency: SM Entertainment Group: Hearts2Hearts Position: Vocalist, Dancer Character: Toramyu Debut: February 24, 2025, Hearts2Hearts MBTI: INTJ Motto: This too shall pass. Nicknames: First Love Girl, Baby Bunny, Torami, Intro Goddess, Tone Fairy, Hexagon All-rounder, 412-gon, Yu-ha-ha-ho-ho, Ha-mung-i, Baby Otter, Yu-hai, Tyrant, Bungeoppang Goddess.

Born: June 18, 2007 (19 years old), Ulsan Metropolitan City From: Vancouver, British Columbia Nationality: South Korea, Canada (Dual citizenship) Physical: 167cm | Type O | Left-handed Family: Father, Mother, Older brother (born 2002) Agency: SM Entertainment Group: Hearts2Hearts Position: Vocalist Character: Stell-nyang Debut: February 24, 2025, Hearts2Hearts 1st Single: The Chase MBTI: ENTP Motto: Stay true to yourself Nicknames: Pink Princess, Pink Girl, Tteokbokki, Baby Apricot, Gorgeous Chic, Tel-nyangi, Stell-nyang, To-nyangi, Prickly, Nutella, S-ddo-ppi.

Born: December 3, 2008 (17 years old), Goyang-si, Gyeonggi-do From: Icheon-si, Gyeonggi-do Nationality: South Korea Physical: 166cm | Type A | 245mm Family: Father, Mother, Older brother (born 2006), Dog (Haneul, Toy Poodle) Agency: SM Entertainment Group: Hearts2Hearts Position: Main Dancer, Rapper Character: Jju-illian Debut: February 24, 2025, Hearts2Hearts MBTI: ISFP Motto: Effort never betrays you! Nicknames: 2109, Jam-Kuromi, Jueun Oppa, Ju Se-eun.

Born: December 20, 2008 (17 years old), Seoul From: Giheung-gu, Yongin-si, Gyeonggi-do Nationality: South Korea Physical: 170–171cm | Type A Family: Father, Mother (born 1983), Older sister (born 2005), Dog (Aegi, Maltipoo) Agency: SM Entertainment Group: Hearts2Hearts Position: Rapper Character: No-sung-i Debut: February 24, 2025, Hearts2Hearts MBTI: ESFP Motto: Let's not leave regrets over past choices. Nicknames: No-sung-i, Lee Hoon, Serisa.

Born: October 9, 2009 (16 years old), Hyehwa-dong, Jongno-gu, Seoul Nationality: South Korea Physical: 164–165cm | Type B Family: Father, Mother, Cat (Aru, born 2016) Agency: SM Entertainment Group: Hearts2Hearts Position: Center, Dancer Character: Jung Peanut Debut: February 24, 2025, Hearts2Hearts MBTI: ENTP Motto: Live doing everything you want to do, don't do things you'll regret, laughter brings good luck. Nicknames: Jung Peanut, Jung-pamine, Dwae-ing-i, The girl in the blue knit, Eung-an-ian, Duba-ian.

Born: April 19, 2010 (16 years old), Sangbuk-myeon, Yangsan-si, Gyeongsangnam-do Nationality: South Korea Physical: 166cm | Type A Family: Father, Mother, Cat (Rio) Agency: SM Entertainment Group: Hearts2Hearts Position: Vocalist Character: Alssong-Hamssong Debut: February 24, 2025, Hearts2Hearts MBTI: ISTJ Motto: Well begun is half done. Nicknames: Ye-song-i, Kim Yeon, Ae-haem-i, Diamond Maknae, Giant Baby, Boss Baby, Cute Maknae, Maknae on Top, All-rounder Maknae, Mandu FM Maknae, Nayeon-i Yeon, Yeoni.