word | | Military service age and obligation |
| age | Russia | 18-27 years of age for compulsory or voluntary military service; males are registered for the draft at 17 years of age; service obligation - 1 year (conscripts can only be sent to combat ... |
| age | Rwanda | 18 years of age for voluntary military service; no conscription; Rwandan citizenship required (2011) |
| age | Saint Kitts and Nevis | 18 years of age for voluntary military service; no conscription (2010) |
| age | Sao Tome and Principe | 18 years of age (est.) (2004) |
| age | Saudi Arabia | 18 years of age (est.); no conscription (2004) |
| age | Senegal | 18 years of age for voluntary military service; 20 years of age for selective conscript service; service obligation - 2 years; women have been accepted into military service since 2008 (2011) |
| age | Serbia | 18 years of age for voluntary military service; conscription abolished effective December 2010; service obligation - 6 months, with reserve obligation to age 60 for men and age 50 for women (2011) |
| age | Seychelles | 18 years of age for voluntary military service (younger with parental consent); no conscription (2010) |
| age | Sierra Leone | 17 years 6 months of age for male and female voluntary military service (younger with parental consent); no conscription; candidates must be HIV negative (2009) |
| age | Singapore | 18-21 years of age for male compulsory military service; 16 years of age for volunteers; 2-year conscript service obligation, with a reserve obligation to age 40 (enlisted) or age 50 (officers ... |
| age | Slovakia | 18-30 years of age for voluntary military service; no conscription; women are eligible to serve (2011) |
| age | Slovenia | 18-25 years of age for voluntary military service; conscription abolished in 2003 (2010) |
| age | South Africa | 18 years of age for voluntary military service; women are eligible to serve in noncombat roles; 2-year service obligation (2007) |