| Foster City to Smolyan | 6,585.41 mi (10,598.19 km) |
| Foster City to Sofia | 6,485.19 mi (10,436.91 km) |
| Foster City to Sopot | 6,520.10 mi (10,493.09 km) |
| Foster City to Sozopol | 6,597.21 mi (10,617.19 km) |
| Foster City to Sredets | 6,591.18 mi (10,607.49 km) |
| Foster City to Stamboliyski | 6,547.46 mi (10,537.12 km) |
| Foster City to Stara Zagora | 6,553.23 mi (10,546.41 km) |
| Foster City to Svilengrad | 6,606.87 mi (10,632.73 km) |
| Foster City to Svishtov | 6,472.76 mi (10,416.89 km) |
| Foster City to Targovishte | 6,521.66 mi (10,495.59 km) |
| Foster City to Teteven | 6,492.84 mi (10,449.21 km) |
| Foster City to Troyan | 6,504.84 mi (10,468.53 km) |
| Foster City to Tryavna | 6,522.86 mi (10,497.53 km) |
| Foster City to Tutrakan | 6,471.95 mi (10,415.60 km) |
| Foster City to Varna | 6,550.84 mi (10,542.56 km) |
