| Korea Masters | 04/13 01:40 | 5 | Jan Louda v Thammasin, S. | W | 0-2 | |
| Korea Open | 04/05 01:40 | 5 | Thammasin, S. v Shesar Hiren Rhustavito | L | 1-2 | |
| Open de Suisse | 03/24 11:00 | - | Thammasin, S. v Anders Antonsen | L | 1-2 | |
| Open de Suisse | 03/23 11:10 | - | Thammasin, S. v Nhat Nguyen | W | 2-0 | |
| Open d'Angleterre | 03/16 20:25 | 5 | Thammasin, S. v Brian Yang | L | 1-2 | |
| World Championships | 12/12 08:40 | 6 | Tien Chen Chou v Thammasin, S. | L | 2-0 | |
| Indonesia Open | 11/23 05:00 | - | Shesar Hiren Rhustavito v Thammasin, S. | L | 2-1 | |
| Indonesia Masters | 11/17 05:40 | 5 | Thammasin, S. v Jonatan Christie | L | 1-2 | |
| Open d'Angleterre | 03/19 12:00 | 3 | Thammasin, S. v Viktor Axelsen | L | 0-2 | |
| Open d'Angleterre | 03/19 10:00 | 4 | Thammasin, S. v Jonatan Christie | - | Walkover | |
| Open d'Angleterre | 03/17 15:10 | 5 | Pablo Abian v Thammasin, S. | W | 0-2 | |
| Open de Suisse | 03/03 11:35 | 5 | Jayaram, Ajay v Thammasin, S. | L | 2-0 | |
| Open de Thaïlande | 01/19 02:40 | 5 | Srikanth Kidambi v Thammasin, S. | L | 2-0 | |
| Open de Thaïlande | 01/12 05:10 | 5 | Viktor Axelsen v Thammasin, S. | L | 2-0 | |
| Open d'Angleterre | 03/11 20:00 | 5 | Thammasin, S. v Viktor Axelsen | L | 0-2 | |
| Hong Kong Open 2019, MS | 11/13 12:35 | 5 | Cheuk Yiu Lee v Thammasin, S. | L | 2-0 | |
| Fuzhou China Open 2019, MS | 11/06 04:25 | 5 | Parupalli, Kashyap v Thammasin, S. | L | 2-0 | |
| Macau Open 2019, MS | 11/03 05:00 | 1 | Yu Qi Shi v Thammasin, S. | W | 1-2 | |
| Macau Open 2019, MS | 11/02 06:20 | 2 | Thammasin, S. v Sun, F. | W | 2-1 | |
| Macau Open 2019, MS | 11/01 07:00 | 3 | Thammasin, S. v Kodai Naraoka | W | 2-0 | |
| Macau Open 2019, MS | 10/31 05:20 | 4 | Lee, Dong Keun v Thammasin, S. | W | 0-2 | |
| Macau Open 2019, MS | 10/30 02:20 | 5 | Joo Ven Soong v Thammasin, S. | W | 1-2 | |
| Open de France | 10/22 10:50 | 5 | Thammasin, S. v Shesar Hiren Rhustavito | L | 0-2 | |
| Denmark Open | 10/18 14:20 | 3 | Thammasin, S. v Tommy Sugiarto | L | 0-2 | |
| Denmark Open | 10/17 07:20 | 4 | Mark Caljouw v Thammasin, S. | W | 1-2 | |
| Denmark Open | 10/15 07:20 | 5 | Thammasin, S. v Parupalli, Kashyap | W | 2-0 | |
| Korea Open | 09/25 12:00 | 5 | Thammasin, S. v Tien Chen Chou | L | 0-2 | |
| Fuzhou China Open 2019, MS | 09/17 03:30 | 5 | Liew, Daren v Thammasin, S. | L | 2-1 | |
| Akita Masters 2019, MS | 08/15 03:55 | 4 | Thammasin, S. v Shimono, Hashiru | L | 1-2 | |
| Akita Masters 2019, MS | 08/14 00:00 | 5 | Thammasin, S. v Lin, C.-Y. | W | 2-1 |