| ITF W25 Karuizawa | 05/24 04:35 | 25 | Rinon Okuwaki v Natsumi Kawaguchi | 0-6,4-6 | |
| ITF W60 Kurume | 05/17 01:00 | 25 | Natsumi Kawaguchi v Eri Shimizu | 3-6,4-6 | |
| ITF W60 Fukuoka | 05/14 03:00 | 29 | Katie Boulter v Natsumi Kawaguchi | Walkover | |
| ITF W60 Fukuoka | 05/13 04:15 | 28 | Natsumi Kawaguchi v Carol Zhao | 6-1,7-6 | |
| ITF W60 Fukuoka | 05/12 03:35 | 27 | Sara Saito v Natsumi Kawaguchi | 6-1,6-7,6-7 | |
| ITF W60 Fukuoka | 05/11 01:00 | 26 | Natsumi Kawaguchi v Sakura Hosogi | 6-1,6-4 | |
| ITF W60 Fukuoka | 05/10 01:00 | 25 | Aoi Ito v Natsumi Kawaguchi | 4-6,5-7 | |
| ITF W60 Fukuoka | 05/08 04:25 | 54 | Natsumi Kawaguchi v Miho Kuramochi | 6-3,7-5 | |
| ITF W80 Gifu | 05/02 01:00 | 25 | Ayano Shimizu v Natsumi Kawaguchi | 6-1,6-3 | |
| ITF W15 Osaka | 04/23 02:00 | 29 | Miho Kuramochi v Natsumi Kawaguchi | 4-6,1-6 | |
| ITF W15 Osaka | 04/22 02:00 | 28 | Ayano Shimizu v Natsumi Kawaguchi | 5-7,4-6 | |
| ITF W15 Osaka | 04/21 01:00 | 27 | Ya-Hsuan Lee v Natsumi Kawaguchi | 3-6,2-6 | |
| ITF W15 Osaka | 04/20 05:30 | 26 | Natsumi Kawaguchi v Pei-Chi Lee | 6-0,7-5 | |
| ITF W15 Osaka | 04/20 01:35 | 25 | Aely Arai v Natsumi Kawaguchi | 1-6,4-6 | |
| ITF W25 Osaka | 04/10 01:00 | 62 | Anri Nagata v Natsumi Kawaguchi | 7-6,5-7,10-8 | |
| ITF W25 Osaka | 04/09 03:00 | 62 | Kanako Morisaki v Natsumi Kawaguchi | 1-6,3-6 | |
| ITF W25 Kofu | 03/29 03:45 | 25 | Sujeong Jang v Natsumi Kawaguchi | 6-7,7-6,6-0 | |
| ITF W25 Kofu | 03/28 05:35 | 62 | Dabin Kim v Natsumi Kawaguchi | 1-6,4-6 | |
| ITF W25 Kofu | 03/28 00:30 | 62 | Meng Yi Chen v Natsumi Kawaguchi | 0-6,2-6 | |
| ITF W15 Hinode | 03/26 06:00 | 29 | Aoi Ito v Natsumi Kawaguchi | 4-6,3-6 | |
| ITF W15 Hinode | 03/26 00:30 | 28 | Natsumi Kawaguchi v Ayumi Koshiishi | 6-1,6-2 | |
| ITF W15 Hinode | 03/24 00:00 | 27 | Akiko Omae v Natsumi Kawaguchi | 4-6,4-6 | |
| ITF W15 Hinode | 03/23 07:10 | 26 | Gyeong Seo Lee v Natsumi Kawaguchi | 3-6,3-6 | |
| ITF W15 Hinode | 03/22 04:30 | 25 | Kanako Osafune v Natsumi Kawaguchi | 3-6,1-6 | |
| ITF W60 Kyoto | 12/19 03:00 | 45 | Natsumi Kawaguchi v Ramu Ueda | 6-3,4-6,7-10 | |
| ITF W25 Monastir | 12/16 10:10 | 27 | Adithya Karunaratne v Natsumi Kawaguchi | 6-4,6-2 | |
| ITF W25 Monastir | 12/15 08:30 | 26 | Natsumi Kawaguchi v Maria Timofeeva | 2-6,6-2,6-2 | |
| ITF W25 Monastir | 12/14 11:30 | 25 | Alice Rame v Natsumi Kawaguchi | 6-7,3-6 | |
| ITF W25 Monastir | 12/13 10:45 | 19 | Natsumi Kawaguchi v Yaroslava Bartashevich | 6-2,6-3 | |
| ITF W25 Monastir | 12/12 11:00 | 44 | Natsumi Kawaguchi v Liel M Rothensteiner | 6-1,6-1 |