Singapore
21 years of age; universal and compulsory
Sint Maarten
18 years of age; universal
Slovakia
18 years of age; universal
Slovenia
18 years of age, 16 if employed; universal
Solomon Islands
21 years of age; universal
Somalia
18 years of age; universal
South Africa
18 years of age; universal
Spain
18 years of age; universal
Sri Lanka
18 years of age; universal
Sudan
17 years of age; universal