| South San Francisco to Popovo | 6,504.99 mi (10,468.78 km) |
| South San Francisco to Provadia | 6,540.03 mi (10,525.16 km) |
| South San Francisco to Radnevo | 6,564.69 mi (10,564.85 km) |
| South San Francisco to Radomir | 6,483.09 mi (10,433.53 km) |
| South San Francisco to Rakitovo | 6,543.93 mi (10,531.44 km) |
| South San Francisco to Rakovski | 6,544.52 mi (10,532.38 km) |
| South San Francisco to Razgrad | 6,499.30 mi (10,459.61 km) |
| South San Francisco to Razlog | 6,536.12 mi (10,518.87 km) |
| South San Francisco to Ruse | 6,469.45 mi (10,411.58 km) |
| South San Francisco to Samokov | 6,510.06 mi (10,476.93 km) |
| South San Francisco to Sandanski | 6,551.36 mi (10,543.39 km) |
| South San Francisco to Sevlievo | 6,501.67 mi (10,463.42 km) |
| South San Francisco to Shumen | 6,523.59 mi (10,498.70 km) |
| South San Francisco to Silistra | 6,477.43 mi (10,424.42 km) |
| South San Francisco to Sliven | 6,549.04 mi (10,539.66 km) |
