2018 Shimadzu All Japan Indoor Tennis Championships – Singles

Yasutaka Uchiyama was the defending champion but lost in the first round to Michał Przysiężny.

John Millman won the title after defeating Jordan Thompson 7–5, 6–1 in the final.

Seeds
• # 🇦🇺 John Millman (champion)

• # 🇦🇺 Jordan Thompson (final)

• # 🇯🇵 Go Soeda (quarterfinals)

• # 🇫🇷 Stéphane Robert (first round)

• # 🇯🇵 Tatsuma Ito (second round)

• # 🇰🇷 Kwon Soon-woo (second round)

• # 🇵🇱 Hubert Hurkacz (quarterfinals)

• # 🇯🇵 Yasutaka Uchiyama (first round)