When you are in a foreign country, you are subject to its laws and are under its jurisdiction. You can be arrested overseas for actions that may be either legal or considered minor infractions in the United States. Familiarize yourself with legal expectations in the countries you will visit. Country Specific Information include information on unusual patterns of arrests in particular countries, as appropriate.
Some of the offenses for which U.S. citizens have been arrested abroad are:
More than 1/3 of U.S. citizens incarcerated abroad are held on drug charges. Some countries do not distinguish between possession and trafficking, and many have mandatory sentences - even for possession of a small amount of marijuana or cocaine. A number of Americans have been arrested for possessing prescription drugs, particularly tranquilizers and amphetamines that they purchased legally elsewhere. Other U.S. citizens have been arrested for purchasing prescription drugs abroad in quantities that local authorities suspected were for commercial use. If in doubt about foreign drug laws, ask local authorities or the nearest U.S. embassy or consulate.
Possession of Firearms
The places where U.S. citizens most often experience difficulties for illegal possession of firearms are nearby - Mexico, Canada and the Caribbean. Sentences for possession of firearms in Mexico can be up to 30 years. In general, firearms, even those legally registered in the U.S., cannot be brought into a country unless a permit is obtained in advance from the embassy or a consulate of that country and the firearm is registered with foreign authorities on arrival. (Note: There are also strict rules about bringing firearms or ammunition into the U.S; check with U.S. Customs before your trip.
In many countries you can be detained for photographing security-related institutions, such things as police and military installations, government buildings, border areas and transportation facilities. If you are in doubt, ask permission before taking photographs.
Americans have been arrested for purchasing souvenirs that were, or looked like antiques, and which local customs authorities believed were national treasures. This is especially true in Turkey, Egypt, Thailand, and Mexico. Familiarize yourself with any local regulations of antiques. In countries with strict control of antiques, document your purchases as reproductions if that is the case, or if they are authentic, secure the necessary export permit (often from the national museum). It is a good idea to inquire about exporting these items before you purchase them.
Know the rules before you go. Do your homework and learn the laws and customs of the country you will be visiting. Stay out of jail and have a great vacation.