| Isabela to Popovo | 5,507.37 mi (8,863.25 km) |
| Isabela to Provadia | 5,568.56 mi (8,961.73 km) |
| Isabela to Radnevo | 5,512.47 mi (8,871.46 km) |
| Isabela to Radomir | 5,360.96 mi (8,627.63 km) |
| Isabela to Rakitovo | 5,426.76 mi (8,733.52 km) |
| Isabela to Rakovski | 5,465.01 mi (8,795.09 km) |
| Isabela to Razgrad | 5,517.58 mi (8,879.69 km) |
| Isabela to Razlog | 5,397.80 mi (8,686.92 km) |
| Isabela to Ruse | 5,485.08 mi (8,827.39 km) |
| Isabela to Samokov | 5,394.47 mi (8,681.57 km) |
| Isabela to Sandanski | 5,393.95 mi (8,680.73 km) |
| Isabela to Sevlievo | 5,458.96 mi (8,785.34 km) |
| Isabela to Shumen | 5,542.46 mi (8,919.73 km) |
| Isabela to Silistra | 5,541.99 mi (8,918.97 km) |
| Isabela to Sliven | 5,524.83 mi (8,891.35 km) |
