| Foster City to Popovo | 6,508.09 mi (10,473.76 km) |
| Foster City to Provadia | 6,543.26 mi (10,530.36 km) |
| Foster City to Radnevo | 6,567.67 mi (10,569.65 km) |
| Foster City to Radomir | 6,485.73 mi (10,437.77 km) |
| Foster City to Rakitovo | 6,546.66 mi (10,535.83 km) |
| Foster City to Rakovski | 6,547.38 mi (10,536.99 km) |
| Foster City to Razgrad | 6,502.44 mi (10,464.67 km) |
| Foster City to Razlog | 6,538.77 mi (10,523.13 km) |
| Foster City to Ruse | 6,472.55 mi (10,416.56 km) |
| Foster City to Samokov | 6,512.75 mi (10,481.27 km) |
| Foster City to Sandanski | 6,553.96 mi (10,547.57 km) |
| Foster City to Sevlievo | 6,504.61 mi (10,468.15 km) |
| Foster City to Shumen | 6,526.76 mi (10,503.81 km) |
| Foster City to Silistra | 6,480.71 mi (10,429.69 km) |
| Foster City to Sliven | 6,552.10 mi (10,544.59 km) |
