| Provider | Group Practice/Location | Office Phone |
| Simonds, Robert MD | Downtown Clinic - Dermatology | (406) 237-7999 |
| Simonds, Robert MD | Cody Clinic - Dermatology Outreach | (406) 237-7999 |
| Simonton, Eric DC, BS | Freedom Chiropractic | 4062722209 |
| Simpson, Charles FNP-BC | Wheatland Memorial Hospital | (406) 632-4351 |
| Simpson, Charles FNP-BC | Wheatland Memorial Healthcare Clinic | (406) 632-4343 |
| Simpson, Londa LCPC | New Day, Inc | (406) 545-0486 |
| Sims, David MD | Intermountain Health Heart & Vascular - Downtown Cardiac & Vascular Surgery | (406) 238-6820 |
| Sims, David MD | Intermountain Health Heart & Vascular - Gallatin Thoracic & Vascular Surgery Outreach | (406) 613-7999 |
| Singh, Nirmal MD | Cogent Healthcare of MT, PC dba Sound Physicians of MT | (406) 657-7000 |
| Singh, Nirmal MD | Intermountain Health Holy Rosary Hospital | (406) 233-2600 |
| Singh, Nirmal MD | St. Vincent Hospitalists | (406) 237-3850 |
| Singh, Nirmal MD | Cogent Healthcare of MT PC dba Sound Physicians of MT II | (855) 768-6363 |
| Singh, Nirmal MD | Cogent Healthcare of MT, PC dba Sound Physicians of MT II | (253) 682-1710 |
| Sirek, Roger DC | Vitality A Professional Corporation DBA Billings Chiropractic Injury Clinic | (406) 969-3805 |
| Sironi, Rindo MD | Billings OB/GYN Associates PC | (406) 248-3607 |
| Sise, Robert MD | Rimrock Foundation | (406) 248-3175 |
| Sizemore, Dorothy DO | Riverstone Health Clinic | (406) 697-0976 |
| Skarda, David MD | SVHC Fortin Pediatric Specialty Clinic | (406) 237-5300 |
| Slyngstad, Tyler MD | Intermountain Health Heart & Vascular - Cody Clinic | (406) 237-5001 |
| Slyngstad, Tyler MD | Intermountain Health Heart & Vascular - Downtown Cardiothoracic & Vascular Surgery | (406) 237-5001 |
| Slyngstad, Tyler MD | SJMG Heart Center | (406) 723-2420 |
| Slyngstad, Tyler MD | Intermountain Health Heart & Vascular - Butte Clinic | (406) 723-2951 |
| Slyngstad, Tyler MD | Cody Clinic - Cardiology Outreach | (406) 237-5001 |
| Smith, Brian DO | Cogent Healthcare of MT, PC dba Sound Physicians of MT | (406) 657-7000 |
| Smith, Brian DO | St. Vincent Hospitalists | (406) 237-3850 |