| Sleaford to Smolyan | 1,405.07 mi (2,261.24 km) |
| Sleaford to Sofia | 1,301.28 mi (2,094.21 km) |
| Sleaford to Sopot | 1,358.07 mi (2,185.60 km) |
| Sleaford to Sozopol | 1,483.76 mi (2,387.88 km) |
| Sleaford to Sredets | 1,466.98 mi (2,360.87 km) |
| Sleaford to Stamboliyski | 1,373.19 mi (2,209.94 km) |
| Sleaford to Stara Zagora | 1,402.66 mi (2,257.37 km) |
| Sleaford to Svilengrad | 1,454.11 mi (2,340.17 km) |
| Sleaford to Svishtov | 1,339.26 mi (2,155.34 km) |
| Sleaford to Targovishte | 1,403.61 mi (2,258.90 km) |
| Sleaford to Teteven | 1,327.46 mi (2,136.34 km) |
| Sleaford to Troyan | 1,346.37 mi (2,166.77 km) |
| Sleaford to Tryavna | 1,377.59 mi (2,217.01 km) |
| Sleaford to Tutrakan | 1,371.50 mi (2,207.22 km) |
| Sleaford to Varna | 1,458.06 mi (2,346.53 km) |
