word | | Military service age and obligation |
| service | 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 ... |
| service | Slovakia | 17-30 years of age for voluntary military service; conscription abolished in 2006; women are eligible to serve (2007) |
| service | Slovenia | 17 years of age for voluntary military service; conscription abolished in 2003 (2007) |
| service | South Africa | 18 years of age for voluntary military service; women have a long history of military service in noncombat roles dating back to World War I (2004) |
| service | Sri Lanka | 18 years of age for voluntary military service (2007) |
| service | Sudan | 18-30 years of age for compulsory military service; 2-year service obligation (2006) |
| service | Swaziland | 18-30 years of age for male and female voluntary military service; no conscription (2008) |
| service | Sweden | 19 years of age for compulsory military service; conscript service obligation: 7-15 months (Navy), 8-12 months (Air Force); after completing initial service, soldiers have a reserve commitment until age 47 (2006) |
| service | Switzerland | 19 years of age for male compulsory military service; 18 years of age for voluntary male and female military service; the Swiss Constitution states that "every Swiss male is obliged to do ... |
| service | Syria | 18 years of age for compulsory military service; conscript service obligation - 30 months (18 months in the Syrian Arab Navy); women are not conscripted but may volunteer to serve (2004) |
| service | Taiwan | 19-35 years of age for male compulsory military service; service obligation 16 months (to be shortened to 14 months as of July 2007 and to 12 months in 2008); women may enlist ... |
| service | Tajikistan | 18 years of age for compulsory military service; 2-year conscript service obligation (2006) |
| service | Tanzania | 18 years of age for voluntary military service (2007) |
| service | Thailand | 21 years of age for compulsory military service; 18 years of age for voluntary military service; males are registered at 18 years of age; 2-year conscript service obligation (2006) |
| service | Timor-Leste | 18 years of age for voluntary military service; no conscription (2008) |
| service | Togo | 18 years of age for selective compulsory and voluntary military service; 2-year service obligation (2006) |
| service | Trinidad and Tobago | 18 years of age for voluntary military service (16 years of age with parental consent); no conscription (2008) |
| service | Tunisia | 20 years of age for compulsory military service; conscript service obligation - 12 months; 18 years of age for voluntary military service (2007) |
| service | Turkmenistan | 18-30 years of age for compulsory military service; 2-year conscript service obligation (2006) |
| service | Uganda | ... of age for compulsory and voluntary military duty; 18-30 years of age for professionals; 9-year service obligation; the government has stated that recruitment below 18 years of age could occur with ... |
| service | Ukraine | 18-25 years of age for compulsory and voluntary military service; conscript service obligation - 18 months for Army and Air Force, 24 months for Navy (2004) |
| service | United Arab Emirates | 18 years of age (est.) for voluntary military service; 18 years of age for officers and women; no conscription (2008) |
| service | United Kingdom | 16-33 years of age (officers 17-28) for voluntary military service (with parental consent under 18); women serve in military services, but are excluded from ground combat positions and some naval postings; must ... |
| service | Uruguay | 18 years of age for voluntary and compulsory military service; enlistment is voluntary in peacetime, but the government has the authority to conscript in emergencies (2007) |