1. Yenny 0 Weeks
Looking for their 5th member, Yenny trained for just a few days before Wonder Girls held their very first showcase. She auditioned multiple times but failed, however, she was selected to join the legendary group without formal training at JYP.
2. Jiyoung 2 Weeks
Two weeks of training at DSP and Jiyoung debuted in KARA.
3. Eunji 2 Months
After passing her audition, she was quickly added to A Pink as the group already was filled out and they just needed to find the main vocalist. She trained for 2 months at A Cube and A Pink made their debut.
4. Ryeowook 2 Months
He signed a contract with SM after impressing judges with his singing at the CMB Youth ChinChin Festival. Just 2 months to train, he officially debuted in Super Junior.
5. Jiwoo 2 Months
On the day of her audition for DSP Media, Jiwoo was asked to record "Oh NaNa". Just 2 months after her audition, she debuted in KARD.
6. Hyuk 3 Months
After being a contestant on Mnet's survival reality show MyDOL, he was chosen for the final lineup and debuted in VIXX. The rest of his fellow VIXX members had years of training but Hyuk only had 3 months before he debuted.
7. Kyuhyun 3 Months
After joining SM in 2006, he trained for only 3 months before debuting in Super Junior.
8. Hara 3 Months
After Kim Sung-hee left KARA, DSP held auditions. Hara was selected by DSP and after training for 3 months she debuted in KARA.
9. Baekhyun 4 Months
An SM casting agent spotted Baekhyun at the Seoul Institute of the Arts. After signing with SM, he trained for just 4 months before debuting in EXO.
10. Chen 4 Months
After joining as a trainee in S.M. Entertainment's Casting System in 2011, Chen debuted in EXO after training for just 4 months.
11. Jung Yein 4 Months
After passing an audition for Woollim in 2014, Jung Yein debuted in Lovelyz after training for just 4 months.
12. Lai Guan Lin 6 Months
He was signed under Cube Entertainment but after just 6 months of training he went on to debut in Wanna One after being selected for the group through 'Produce 101' season 2.
13. Youngjae 7 Months
Youngjae was a trainee for just 7 months at JYP before he was selected to debut in GOT7.
14. Seungri 10 Months
After being eliminated on 'Let's Coke Play! Battle Shinhwa', Seungri was scouted to join YG. He was also eliminated on 'BIG BANG Documentary' but was later given one final opportunity to impress Yang Hyun Suk. He succeeded and debuted in Big Bang after just 10 months of training.
15. Suzy 10 Months
She was eliminated from Mnet's 'Superstar K' in 2009 but a JYP scout saw potential and she became a trainee. After just 10 months of training, she debuted in miss A.