| Thailand Open | 05/19 07:40 | 4 | Kai Schaefer v Zii Jia Lee | L | 0-2 | |
| Thailand Open | 05/18 10:00 | 5 | Thomas Rouxel v Kai Schaefer | W | 0-2 | |
| Thomas Cup | 05/11 07:40 | - | Kai Schaefer v Jason Anthony Ho-Shue | W | 2-0 | |
| Thomas Cup | 05/09 07:40 | - | Tzu Wei Wang v Kai Schaefer | L | 2-1 | |
| Thomas Cup | 05/08 02:40 | - | Srikanth Kidambi v Kai Schaefer | L | 2-1 | |
| Europameisterschaft | 04/26 11:00 | - | Kai Schaefer v Anders Antonsen | L | 1-2 | |
| Korea Open | 04/05 03:50 | 5 | Donghun Kim v Kai Schaefer | L | 2-0 | |
| Orleans Masters | 03/30 11:00 | - | Kai Schaefer v Chico Aura Dwi Wardoyo | L | 0-2 | |
| Polish Open | 03/25 14:30 | - | Kai Schaefer v Jun Hao Leong | L | 0-2 | |
| Polish Open | 03/25 08:40 | - | Kai Schaefer v Luka Wraber | W | 2-0 | |
| Swedish Open | 01/22 15:40 | - | Seng Zoe Yeoh v Kai Schaefer | L | 2-0 | |
| Swedish Open | 01/22 09:40 | - | Rasmus Messerschmidt v Kai Schaefer | W | 1-2 | |
| Swedish Open | 01/21 16:30 | - | Jacob Nilsson v Kai Schaefer | W | 1-2 | |
| Swedish Open | 01/21 10:20 | - | Jeppe Bruun v Kai Schaefer | W | 0-2 | |
| Weltmeisterschaft | 12/15 12:00 | 6 | Kai Schaefer v Kantaphon Wangcharoen | L | 0-2 | |
| Weltmeisterschaft | 12/12 08:00 | 6 | Kwang Hee Heo v Kai Schaefer | - | Walkover | |
| Belgian International | 10/28 08:30 | 5 | Ade Resky Dwicahyo v Kai Schaefer | L | 2-1 | |
| Olympische Spiele 2020 - Herren | 07/27 01:40 | 1 | Toby Penty v Kai Schaefer | L | 2-0 | |
| Olympische Spiele 2020 - Herren | 07/25 11:00 | 1 | Kantaphon Wangcharoen v Kai Schaefer | L | 2-0 | |
| Spain International | 06/17 15:00 | - | Ivan Rusev v Kai Schaefer | L | 2-0 | |
| Spain Masters | 05/19 11:20 | 5 | Kai Schaefer v Lucas Claerbout | L | 1-2 | |
| Portuguese Int. | 05/07 14:30 | 1 | Kai Schaefer v Johnnie Torjussen | L | 0-2 | |
| Europameisterschaft | 04/28 12:20 | 1 | Kai Schaefer v Anders Antonsen | L | 0-2 | |
| Orleans Masters | 03/25 11:30 | 4 | Kai Schaefer v Ditlev Jaeger Holm | L | 0-2 | |
| Orleans Masters | 03/24 17:10 | 5 | Mithun Manjunath v Kai Schaefer | W | 1-2 | |
| SaarLorLux Open | 10/27 11:15 | 6 | Kai Schaefer v Lucas Corvee | L | 0-2 | |
| Denmark Open | 10/13 10:10 | 5 | Kai Schaefer v Brice Leverdez | L | 0-2 | |
| Spain Masters | 02/20 11:50 | 4 | Kai Schaefer v Sameer Verma | L | 1-2 | |
| Spain Masters | 02/19 15:00 | 5 | Kai Schaefer v Misha Zilberman | W | 2-1 | |
| Europameisterschaft - Team | 02/14 14:00 | - | Viktor Axelsen v Kai Schaefer | L | 2-0 |
Kai Schäfer (* 13. Juni 1993 in Darmstadt) ist ein deutscher Badmintonspieler. Er spielt seit der Saison 2020/2021 wieder für den SV Fun-Ball Dortelweil in der 1. Bundesliga.