| Full Name | Yoon Seo-yeon |
| Stage Name | SeoYeon |
| Native Name | 윤서연 |
| Birthday | August 6, 2003 |
| Age | 21 years and 10 months old |
| Zodiac Sign | Leo |
| Birthplace | Kyochon-dong, Yuseong-gu, Daejeon, South Korea |
| Height | 5’3″ (160 cm) |
| Weight | – |
| Blood Type | B |
| MBTI | ISFP |
| Education | Chungnam Girls’ High School |
| Languages | Korean, English, Japanese |
| Group | TripleS |
| Social Media | – |