2019 Keio Challenger

The 2019 Keio Challenger was a professional tennis tournament played on hardcourts. It was the 14th (men's) and third (women's) editions of the tournament and part of the 2019 ATP Challenger Tour and the 2019 ITF Women's World Tennis Tour. It took place in Yokohama, Japan between 25 February and 10 March 2019.

Seeds

 * 1 rankings are as of 18 February 2019

Other entrants
The following players received wildcards into the singles main draw:
 * 🇯🇵 Shinji Hazawa
 * 🇯🇵 Masamichi Imamura
 * 🇯🇵 Naoto Kai
 * 🇰🇷 Sung Yo-han
 * 🇯🇵 Kaito Uesugi

The following player received entry into the singles main draw using a protected ranking:
 * 🇺🇸 Daniel Nguyen

The following players received entry into the singles main draw using their ITF World Tennis ranking:
 * 🇹🇳 Moez Echargui
 * 🇷🇺 Ivan Gakhov
 * 🇹🇳 Skander Mansouri
 * 🇪🇸 David Pérez Sanz

The following players received entry from the qualifying draw:
 * 🇰🇷 Kim Cheong-eui
 * Tseng Chun-hsin

The following player received entry as a lucky loser:
 * 🇯🇵 Shintaro Imai

Seeds

 * 1 rankings are as of 25 February 2019.

Other entrants
The following players received wildcards into the singles main draw:
 * 🇯🇵 Ayumi Hirata
 * 🇯🇵 Anri Nagata
 * 🇯🇵 Risa Ozaki
 * 🇯🇵 Satoko Sueno

The following players received entry into the singles main draw using their ITF World Tennis ranking:
 * Lee Hua-chen
 * 🇹🇭 Nudnida Luangnam
 * 🇷🇺 Anna Morgina
 * 🇯🇵 Naho Sato
 * 🇷🇺 Anna Ureke

The following players received entry from the qualifying draw:
 * 🇯🇵 Mayuka Aikawa
 * 🇯🇵 Shiho Akita
 * 🇺🇸 Catherine Harrison
 * 🇯🇵 Kyōka Okamura
 * 🇯🇵 Akiko Omae
 * 🇯🇵 Risa Ushijima

Men's singles

 * 🇰🇷 Kwon Soon-woo def. 🇩🇪 Oscar Otte 7–6(7–4), 6–3.

Women's singles

 * 🇧🇪 Greet Minnen def. 🇷🇴 Elena-Gabriela Ruse, 6–4, 6–1

Men's doubles

 * 🇹🇳 Moez Echargui / 🇹🇳 Skander Mansouri def. 🇦🇺 Max Purcell / 🇦🇺 Luke Saville 7–6(8–6), 6–7(3–7), [10–7].

Women's doubles

 * 🇰🇷 Choi Ji-hee / 🇰🇷 Han Na-lae def. 🇮🇳 Rutuja Bhosale / 🇯🇵 Akiko Omae, 6–1, 7–5