| Code | Name | Continent | Region |
| ROM | Romania | Europe | Eastern Europe |
| RUS | Russian Federation | Europe | Eastern Europe |
| RWA | Rwanda | Africa | Eastern Africa |
| SAU | Saudi Arabia | Asia | Middle East |
| SDN | Sudan | Africa | Northern Africa |
| SEN | Senegal | Africa | Western Africa |
| SGP | Singapore | Asia | Southeast Asia |
| SGS | South Georgia and the South Sandwich Islands | Antarctica | Antarctica |
| SHN | Saint Helena | Africa | Western Africa |
| SJM | Svalbard and Jan Mayen | Europe | Nordic Countries |
| SLB | Solomon Islands | Oceania | Melanesia |
| SLE | Sierra Leone | Africa | Western Africa |
| SLV | El Salvador | North America | Central America |
| SMR | San Marino | Europe | Southern Europe |
| SOM | Somalia | Africa | Eastern Africa |
| SPM | Saint Pierre and Miquelon | North America | North America |
| SSD | South Sudan | Africa | Northern Africa |
| STP | Sao Tome and Principe | Africa | Central Africa |
| SUR | Suriname | South America | South America |
| SVK | Slovakia | Europe | Eastern Europe |