Age requirements for tattoos and piercing vary by country and state. As of 2014, in most states it is illegal to tattoo or pierce any body part of a person under the age of 18 without parental consent.
In most states and countries, it is possible for persons over 14 years old to legally get a tattoo or piercing with parental consent. Without parental consent, one generally must be over the age of 18 (although the age limit is 16 in some countries) and must bring proper documentation as proof of age. Tattoo and piercing parlors will know the local laws.