2018 Seoul Open Challenger

The 2018 Seoul Open Challenger was a professional tennis tournament played on outdoor hard courts. It was the fourth edition of the tournament. It was part of the 2018 ATP Challenger Tour. It took place in Seoul, South Korea, between 30 April and 6 May 2018.

Seeds

 * 1 Rankings as of 23 April 2018.

Other entrants
The following players received wildcards into the singles main draw:
 * 🇰🇷 Chung Yun-seong
 * 🇰🇷 Hong Seong-chan
 * 🇰🇷 Kim Young-seok
 * 🇰🇷 Park Ui-sung

The following player received entry into the singles main draw as a special exempt:
 * 🇵🇱 Kamil Majchrzak

The following players received entry from the qualifying draw:
 * 🇯🇵 Makoto Ochi
 * 🇰🇷 Son Ji-hoon
 * 🇯🇵 Renta Tokuda
 * 🇯🇵 Yosuke Watanuki

Singles

 * 🇺🇸 Mackenzie McDonald def. 🇦🇺 Jordan Thompson 1–6, 6–4, 6–1.

Doubles

 * 🇯🇵 Toshihide Matsui / Frederik Nielsen def.  Chen Ti /  Yi Chu-huan 6–4, 7–6(7–3).