Wiktionary
n. Travel to a jurisdiction other than one's home jurisdiction for the purpose of sexual intercourse with prostitutes or for the purpose of engaging in sex acts which are prohibited in one's home jurisdiction.
Wikipedia
Sex tourism is travel to engage in sexual activity, particularly with prostitutes. The World Tourism Organization, a specialized agency of the United Nations, defines sex tourism as "trips organized from within the tourism sector, or from outside this sector but using its structures and networks, with the primary purpose of effecting a commercial sexual relationship by the tourist with residents at the destination".
Some people regard sexual activity while traveling as a way of enhancing their travel experience. However, social problems arise when particular countries or cities acquire a reputation as a destination or become attractive for sex tourism. Attractions for sex tourists can include lower costs for sexual services in the destination country, more favorable local attitudes to prostitution, separation from person's normal social circle and physical environment, because prostitution is either legal or there is indifferent law enforcement, and access to child prostitution.