Upon entry to a country, passengers must declare to a customs official all items purchased in a foreign country. Each country has a set limit on the value of merchandise that can be brought back into the country of residence.

Returning U.S. residents are entitled to a $400 dollar exemption from paying duty on goods that would otherwise be dutiable. Articles acquired abroad with a total value of up to $400 will be admitted duty-free, provided that they accompany the passenger. Additional acquisitions may qualify for duty-free treatment under other exemption authorities, such as the Generalized System of Preferences, which awards duty-free treatment to many goods from developing countries. Fine art (not handicrafts) and antiques over 100 years old are commonly acquired items that also do not require the payment of duty. The exemption applies to each purchase acquired abroad.

For items purchased in American Samoa, Guam, or the U.S. Virgin Islands, the exemption is $1,200. Under the terms of the Caribbean Basin Economic Recovery Act, articles purchased in any of 24 Caribbean countries qualify for a $600 exemption.

Not more than 100 cigars or 200 cigarettes (one carton) may be included in the $400 exemption. One liter (33.8 fl. oz.) of alcoholic beverages may be included in the exemption, provided that the traveler is 21 years of age or older, the beverages are for his or her personal use, and no state laws are violated.

For total purchases exceeding the exemption, a flat 10 percent duty is applied to the next $1,000 worth (fair retail value) of merchandise. Any dollar amount of articles over $1,000 is dutiable at the various rates of duty applicable to the articles.

Certain articles considered detrimental to the general welfare are prohibited entry by law. Among these are lottery tickets, narcotics and dangerous drugs, obscene publications, treasonable materials, hazardous articles such as fireworks or toxic substances, and switchblade knives.

The head of a family may make a joint declaration for all members residing in the same household and returning together to the U.S., including children. Thus, while one family member may have articles that exceed his or her personal exemption, when combined together with the articles of the whole family, they may not be subject to any duty.

Similar limits may apply to visitors who transport personal possessions into a destination country. For example, passengers entering Greece are limited to 200 cigarettes, five boxes of matches, two packs of playing cards, one liter of alcoholic beverages, and $150 worth of new articles purchased in a duty-free shop. Customs limits vary from one country to another. Under certain circumstances, photographic equipment, clothing, jewelry, and other personal effects must be declared to a customs official on entering a foreign country.

There are also limits on the amount of cash currency that may be brought into a foreign country by passengers. Such limits also often apply to currency taken out of the country by residents as well as visitors. There is no limit on the amount of cash or monetary instruments that may be taken from or brought in the United States; however, travelers transporting more than $10,000 are required to file Customs Form 4790.