| Challenger Lexington | 08/03 15:00 | 27 | [372] Collin Altamirano v Joris De Loore [377] | Retired | |
| Challenger Lexington | 08/01 15:10 | 26 | [305] Joao Menezes v Collin Altamirano [372] | 3-6,4-6 | |
| Challenger Lexington | 07/31 01:35 | 25 | [352] Hugo Grenier v Collin Altamirano [372] | 7-6,6-7,4-6 | |
| ITF USA F19B | 07/21 15:30 | 28 | [245] Evgeny Karlovskiy v Collin Altamirano [387] | 6-4,6-4 | |
| ITF USA F19B | 07/20 16:00 | 27 | Collin Altamirano v Kareem Al Allaf | 6-4,6-2 | |
| ITF USA F19B | 07/19 20:50 | 26 | [387] Collin Altamirano v Bernardo Saraiva [257] | 6-3,6-4 | |
| ITF USA F19B | 07/17 15:00 | 25 | Collin Altamirano v Will Davies | 6-1,6-2 | |
| Challenger Winnetka | 07/13 19:20 | 28 | [155] Jason Jung v Collin Altamirano [490] | 6-2,6-2 | |
| Challenger Winnetka | 07/12 19:15 | 27 | [490] Collin Altamirano v Mitchell Krueger [220] | 6-4,6-4 | |
| Challenger Winnetka | 07/11 18:00 | 26 | [160] Darian King v Collin Altamirano [490] | 5-7,6-7 | |
| Challenger Winnetka | 07/10 16:30 | 25 | [366] Austin Krajicek v Collin Altamirano [490] | 5-7,5-7 | |
| Challenger Winnetka Qual | 07/09 16:50 | 54 | Emil Reinberg v Collin Altamirano | 3-6,4-6 | |
| Challenger Winnetka Qual | 07/08 16:35 | 46 | Logan Smith v Collin Altamirano | 2-6,3-6 | |
| Challenger Winnetka Qual | 07/07 15:00 | 45 | Sam Riffice v Collin Altamirano | 6-7,6-3,4-6 | |
| ITF USA F19 | 07/05 17:30 | 26 | Collin Altamirano v Reese Stalder | 3-6,1-6 | |
| ITF USA F19 | 07/04 14:00 | 25 | Collin Altamirano v Samuel Beren | 6-2,6-3 | |
| ITF USA F17 | 06/26 19:00 | 25 | Collin Altamirano v Jeffrey John Wolf | 4-6,5-7 | |
| ITF USA F15 | 06/20 14:00 | 25 | Trevor A Johnson v Collin Altamirano | Retired | |
| ITF Singapore F2 | 05/26 03:00 | 29 | Takuto Niki v Collin Altamirano | 6-7,3-6 | |
| ITF Singapore F2 | 05/25 03:00 | 28 | Kazuki Nishiwaki v Collin Altamirano | 7-5,2-6,3-6 | |
| ITF Singapore F2 | 05/24 03:00 | 27 | Collin Altamirano v Shintaro Imai | 6-2,6-2 | |
| ITF Singapore F2 | 05/23 02:00 | 26 | Collin Altamirano v Karunuday Singh | 6-2,6-3 | |
| ITF Singapore F2 | 05/22 02:00 | 25 | Collin Altamirano v Hong Kit Wong | 6-0,3-6,6-3 | |
| ITF China F6 | 05/16 02:00 | 26 | Patrik Niklas-Salminen v Collin Altamirano | 7-6,7-5 | |
| ITF China F6 | 05/14 04:35 | 25 | Francis Casey Alcantara v Collin Altamirano | 1-6,0-6 | |
| ITF USA F10 | 04/13 16:20 | 27 | Harrison Adams v Collin Altamirano | 4-6,6-3,6-4 | |
| ITF USA F10 | 04/12 17:20 | 26 | Vasil Kirkov v Collin Altamirano | 1-6,7-5,2-6 | |
| ITF USA F10 | 04/11 15:00 | 25 | Collin Altamirano v Scott Griekspoor | 7-6,6-3 | |
| ITF USA F9 | 04/07 15:30 | 27 | Scott Griekspoor v Collin Altamirano | 7-6,6-2 | |
| ITF USA F9 | 04/05 15:00 | 26 | Collin Altamirano v Liam Caruana | 6-2,6-4 |