| ITF M25 Canberra | 03/16 23:00 | 27 | Colin Sinclair v Tatsuma Ito | 4-6,4-6 | |
| ITF M25 Canberra | 03/16 00:30 | 26 | [417] Colin Sinclair v Jeremy Beale [325] | 6-2,6-2 | |
| ITF M25 Canberra | 03/14 02:00 | 25 | [417] Colin Sinclair v Calum Puttergill [219] | 6-3,6-2 | |
| Challenger Pune | 02/27 05:30 | 19 | [443] Akira Santillan v Colin Sinclair [426] | 6-7,7-5,6-2 | |
| Challenger Pune | 02/26 05:30 | 14 | Colin Sinclair v S D Prajwal Dev | 6-3,6-4 | |
| Challenger Pune | 02/26 05:30 | 14 | Colin Sinclair v Vladyslav Orlov | Cancelled | |
| Challenger Bengaluru | 02/20 07:30 | 19 | [426] Colin Sinclair v Alibek Kachmazov [342] | 5-7,2-6 | |
| Challenger Bengaluru | 02/19 11:50 | 14 | [313] Jay Clarke v Colin Sinclair [461] | 4-6,5-7 | |
| Challenger Manama | 02/15 11:15 | 26 | [115] Tomas Machac v Colin Sinclair [461] | 6-0,6-2 | |
| Challenger Manama | 02/14 11:35 | 25 | [461] Colin Sinclair v Andrea Arnaboldi [335] | 7-6,2-6,6-3 | |
| Challenger Manama | 02/13 11:30 | 19 | [335] Andrea Arnaboldi v Colin Sinclair [461] | 6-4,7-6 | |
| Challenger Manama | 02/12 13:30 | 14 | Koray Kirci v Colin Sinclair | 3-6,2-6 | |
| Davis Kupa | 02/04 16:30 | 45 | Darian King v Colin Sinclair | 7-6,6-3 | |
| Davis Kupa | 02/03 16:40 | 45 | Kaipo Marshall v Colin Sinclair | 2-6,1-6 | |
| ITF M25 Wesley Chapel | 01/27 16:55 | 27 | [458] Colin Sinclair v Zachary Svajda [292] | 1-6,0-6 | |
| ITF M25 Wesley Chapel | 01/26 16:00 | 26 | Colin Sinclair v Patrick Kypson | 6-4,6-1 | |
| ITF M25 Wesley Chapel | 01/25 20:45 | 25 | Colin Sinclair v Connor Farren | 6-3,6-4 | |
| UTR Pro Pozos | 01/22 15:00 | - | Colin Sinclair v Anthony Wright | 7-6,5-4 | |
| UTR Pro Pozos | 01/21 15:00 | - | Colin Sinclair v Krish Arora | 6-1,6-1 | |
| UTR Pro Pozos | 01/20 22:43 | - | Alexander Aney v Colin Sinclair | 4-6,4-6 | |
| UTR Pro Pozos | 01/19 23:30 | - | Luciano Doria v Colin Sinclair | 7-6,6-7,2-5 | |
| UTR Pro Pozos | 01/17 23:45 | - | Christian Heaney-Secord v Colin Sinclair | 2-6,3-6 | |
| UTR Pro Pozos | 01/16 22:00 | - | Colin Sinclair v Gerardo L Villasenor | 6-2,6-7,6-7 | |
| Challenger Noumea | 01/04 00:30 | 26 | [477] Colin Sinclair v Ryan Peniston [167] | 6-4,4-6,3-6 | |
| Challenger Noumea | 01/02 05:00 | 25 | [477] Colin Sinclair v Ajeet Rai [466] | 7-5,6-4 | |
| Challenger Yokkaichi | 11/25 03:50 | 27 | [498] Colin Sinclair v Frederico Ferreira Silva [244] | 2-6,6-3,3-6 | |
| Challenger Yokkaichi | 11/24 04:15 | 26 | Yuichi Sugita v Colin Sinclair | 4-6,3-6 | |
| Challenger Yokkaichi | 11/22 01:00 | 25 | [280] Ramkumar Ramanathan v Colin Sinclair [498] | 2-6,2-6 | |
| Challenger Yokkaichi | 11/21 01:00 | 19 | Colin Sinclair v Koki Matsuda | 6-3,6-4 | |
| Challenger Yokkaichi | 11/20 03:30 | 14 | Colin Sinclair v Renta Tokuda | 6-1,7-5 |
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.