| Full Name | Kim Si-yoon |
| Stage Name | Siyoon |
| Native Name | 김시윤 |
| Birthday | February 16, 2005 |
| Age | 20 years and 5 months old |
| Zodiac Sign | Aquarius |
| Birthplace | Gwangmyeong, Gyeonggi-do, South Korea |
| Height | 5’8″ (173 cm) |
| Weight | 105.8 lbs (48 kg) |
| Blood Type | B |
| MBTI | INFP |
| Education | Gwanghee Middle School |
| Languages | Korean, Japanese, English |
| Groups | Billlie (2021-present) Moon Sua X Siyoon (2025-present) |
| Social Media | Instagram: [@see_uniuni] Twitter (X): [@SEE_UniUni] |