1998 Japan Open Tennis Championships – Women's singles

First-seeded Ai Sugiyama was the defending champion and won in the final 6–3, 6–3 against Corina Morariu.

Seeds
A champion seed is indicated in bold text while text in italics indicates the round in which that seed was eliminated. The top two seeds received a bye to the second round.


 * 1) 🇯🇵 Ai Sugiyama (champion)
 * 2) 🇯🇵 Naoko Sawamatsu (quarterfinals)
 * 3) 🇹🇭 Tamarine Tanasugarn (second round)
 * 4) 🇺🇸 Amy Frazier (semifinals)
 * 5) 🇺🇸 Corina Morariu (final)
 * 6)  Shi-Ting Wang (semifinals)
 * 7) 🇯🇵 Miho Saeki (first round)
 * 8) 🇯🇵 Yuka Yoshida (second round)