| Challenger Noumea | 01/03 09:40 | 26 | [400] Colin Sinclair v Benoit Paire [117] | 6-4,2-6,2-6 | |
| Challenger Noumea | 01/02 02:40 | 25 | [452] Rubin Statham v Colin Sinclair [400] | 7-6,4-6,4-6 | |
| Challenger Yokkaichi | 11/26 04:35 | 14 | [366] Colin Sinclair v Ray Ho [173] | 3-6,5-7 | |
| Challenger Yokohama | 11/21 03:45 | 25 | [366] Colin Sinclair v Mathys Erhard [342] | 3-6,2-6 | |
| Challenger Yokohama | 11/20 03:30 | 19 | [306] Giovanni Fonio v Colin Sinclair [361] | 3-6,7-5,6-7 | |
| Challenger Yokohama | 11/19 07:55 | 14 | [484] Nathan Ponwith v Colin Sinclair [361] | 3-6,6-7 | |
| Challenger Kobe | 11/12 01:00 | 14 | [387] James Trotter v Colin Sinclair [361] | 6-4,7-5 | |
| Challenger Sydney | 10/30 04:05 | 25 | [353] Colin Sinclair v Marc Polmans [160] | 4-6,2-6 | |
| Challenger Shenzhen | 10/19 07:55 | 26 | [362] Colin Sinclair v Lorenzo Giustino [290] | 3-6,4-6 | |
| Challenger Shenzhen | 10/16 07:00 | 26 | [228] Evgeny Donskoy v Colin Sinclair [362] | 6-2,3-6,4-6 | |
| Challenger Shenzhen | 10/11 03:40 | 25 | [69] Thanasi Kokkinakis v Colin Sinclair [347] | 6-2,3-6,6-3 | |
| Challenger Shenzhen | 10/10 04:00 | 19 | [347] Colin Sinclair v Tsung-Hao Huang [400] | 3-6,6-4,6-2 |
Colin Sinclair (born December 19, 1994) is a Northern Mariana Islander tennis player.
He achieved a career best singles ranking of world No. 340 on 18 September 2023, and a career high doubles ranking of world No. 200 on 10 April 2023. He has won 2 singles titles on the ITF Futures Tour. Additionally, he has won 2 titles on ATP Challenger Tour and 7 titles on the ITF Futures Tour in doubles.
He represents his country in Davis Cup as part of the Pacific Oceania team since 2017 and has a career record of 18–5 (13–3 in singles, 5–2 in doubles) in the competition. He has been coached by Jeff Race, Ian Malpass, and Silviu Tanasoiu.