| Fort Irwin Stowe | Eastern Time | -03:00 |
| Fort Irwin Story City | Central Time | -02:00 |
| Fort Irwin Stonington | Eastern Time | -03:00 |
| Fort Irwin Stony Plain | Mountain Time | -01:00 |
| Fort Irwin Stonyfell | Central Australia Time | -18:30 |
| Fort Irwin Street | United Kingdom Time | -08:00 |
| Fort Irwin Strassen | Central European Time | -09:00 |
| Fort Irwin Stratham | Eastern Time | -03:00 |
| Fort Irwin Strangford | United Kingdom Time | -08:00 |
| Fort Irwin Strasburg | Eastern Time | -03:00 |
| Fort Irwin Strömstad | Central European Time | -09:00 |
| Fort Irwin Střílky | Central European Time | -09:00 |
| Fort Irwin Stroudsburg | Eastern Time | -03:00 |
| Fort Irwin Sturbridge | Eastern Time | -03:00 |
| Fort Irwin Sturgis | Mountain Time | -01:00 |
| Fort Irwin Štúrovo | Central European Time | -09:00 |
| Fort Irwin Subang | Western Indonesia Time | -15:00 |
| Fort Irwin Subiaco | Western Australia Time | -16:00 |
| Fort Irwin Suan Dok | Indochina Time | -15:00 |
| Fort Irwin Stuttgart | Central Time | -02:00 |
| Fort Irwin Stutzheim-Offenheim | Central European Time | -09:00 |
| Fort Irwin Silveira | Western European Time | -08:00 |
| Fort Irwin Silverton | Pacific Time | 00:00 |
| Fort Irwin Silay City | Philippine Time | -16:00 |
| Fort Irwin Sinaia | Eastern European Time | -10:00 |
| Fort Irwin Stevensville | Eastern Time | -03:00 |
| Fort Irwin Stewiacke | Atlantic Time | -04:00 |
| Fort Irwin Simrishamn N | Central European Time | -09:00 |
| Fort Irwin Simpang Ampat | Malaysia Time | -16:00 |
| Fort Irwin Simpang Renggam | Malaysia Time | -16:00 |
| Fort Irwin Stone Harbor | Eastern Time | -03:00 |
| Fort Irwin Stone Mountain | Eastern Time | -03:00 |
| Fort Irwin Stonegate | United Kingdom Time | -08:00 |
| Fort Irwin Stirling | Mountain Time | -01:00 |
| Fort Irwin Stilton | United Kingdom Time | -08:00 |
| Fort Irwin Zahara de los Atunes | Central European Time | -09:00 |
| Fort Irwin Zachary | Central Time | -02:00 |
| Fort Irwin Yzeure | Central European Time | -09:00 |