Cancun is a popular tourist destination in Mexico, a nation that has relatively few restrictions on visitors from the United States.

Dozens of countries in Europe and Asia remain off-limits for American travelers as the world continues to struggle with the COVID-19 pandemic. Other countries do remain open, with and without quarantine, to Americans who can meet certain conditions.

Many, such as Albania, are off the beaten path for most Americans. Others, such as Mexico, are more familiar. At least two of those nations, Aruba and Costa Rica, have different policies depending on which U.S. state you are from.

Unfortunately, you won’t find Canada on the open list. Canada has banned most foreign nationals, including U.S. citizens, from entering its territory. There are exceptions for some students and people with Canadian family, but otherwise, the ban on nonessential travel is firm.

The U.S.’s other neighbor, Mexico, requires no test and no quarantine for those traveling by air. Under a pact the two countries have been renewing monthly, U.S. travelers are forbidden from traveling by land across the border for nonessential reasons, but no such ban applies to those who fly. That large loophole, by the way, is often unacknowledged in Department of Homeland Security communications.

Regarding those European nations: If you aren’t familiar with the term “Schengen countries,” you should be. The term refers to 26 European Union nations that are acting collectively when it comes to allowing travelers to safely cross their borders without spreading COVID-19. Americans currently are not allowed in; residents of Canada, New Zealand and Japan are. The list is reviewed every two weeks.

In Asia, many doors are also closed. American tourists are not allowed to visit Japan, Vietnam, Thailand and the Philippines.

What To Consider

Before you make plans for going abroad, bear in mind that travel increases your risk of infection and the chance that you might unknowing pass infection to others, worsening a catastrophe that has already claimed 1 million lives. Since March, local, state and national health officials have all urged Americans to stay close to home — preferably within their neighborhoods — and defer any nonessential travel.

The national Centers for Disease Control and Prevention have country-by-country information on COVID-19 cases and deaths (with countries assessed four levels of risk), and the World Health Organization maintains an updated dashboard.

Travelers should remember that restrictions may depend not only on the destination but also on airports you pass through on the way to your destination. Temperature testing, mask requirements and social distancing are the rule globally, not the exception. Also, if you need a new or renewed passport, federal officials say the usual wait is now 10 to 12 weeks. The agency had a processing backlog of more than 930,000 passports as of Sept. 28.

Finally, remember that as infection rates and geopolitics change, entry requirements and State Department advice change. Check websites from the State Department about your destination.

Until more is known about reopening on a global scale, here are countries that might let you in — if you know the rules.

No Tests/Quarantines Required

Albania: You don’t need a COVID-19 test to get into the country, but you may be subject to health screenings at airports and other ports of entry, according to the U.S. Embassy in Albania. Flights to the country resumed June 15. Note there are no direct flights to Albania from the U.S., meaning you’ll have to consider what country you will pass through and what restrictions apply. Face coverings are required for indoor spaces, including public transportation.

Brazil: You can fly in, but land borders and ports remain closed to foreign travelers at least through Oct. 23, according to the U.S. Embassy & Consulates in Brazil. As of Sept. 24, those who arrive by plane are required to have proof of health insurance for a short stay of up to 90 days. The insurance must be valid for the time you’re in the country, with a minimum coverage of 30,000 Brazilian reals, or about $5,314. Several states and regions require face coverings.

Dominican Republic: You may be subject to a COVID-19 rapid test and/or a temperature check when you arrive, according to the U.S. Embassy. COVID-19 tests are performed on “randomly selected travelers.” Also, the Dominican Republic on Sept. 28 issued a nationwide curfew that’s strictly enforced from 9 p.m. to 5 a.m. Mondays through Fridays, and 7 p.m. to 5 a.m. on Saturdays and Sundays.

Kosovo: The country is open to all travelers. Commercial flights are operating at Pristina International Airport in the capital. The country imposes curfews on businesses such as restaurants from 11:30 p.m. to 5 a.m., according to the U.S. Embassy in Kosovo.

Mexico: American tourists who arrive by air face no COVID-19 testing or quarantine requirements. An agreement between the two countries bans most Americans from crossing into Mexico by land for nonessential reasons.

North Macedonia: Americans are allowed to enter without COVID-19 restrictions or test required, according to the U.S. Embassy. Arriving passengers are subject to a thermal screening at passport control.

Serbia: Americans are allowed to enter without restrictions. Face coverings are required for indoor locations and recommended for outdoors.

Tanzania: No quarantine requirements. Visitors may have to present COVID-19 test results on arrival.

Turkey: Americans are allowed, with no COVID-19 test or quarantine required if they are free of symptoms.

Tests Required

Antigua and Barbuda: Passengers arriving by air must have proof of a negative COVID-19 test (real-time polymerase chain reaction) taken within the seven days before their flights.

Aruba: Restrictions set on American visitors depend on virus rates in the state they’re coming from. As of Sept 24, visitors from California were urged to get a COVID-19 test 12 to 72 hours ahead of their flights. There is a second option, however: a molecular (nasal swab) PCR COVID-19 test at the airport on arrival and wait up to 24 hours for results in your hotel room.

Armenia: The U.S. Embassy reports that Americans are permitted to enter by air and are required to “complete health questionnaires and self-quarantine or self-monitor for 14 days or submit to a PCR test. Individuals who choose to take a PCR (COVID-19) test and receive a negative result may be exempted from self-quarantine requirements.”

Barbados: Americans are permitted, but as residents of a country currently defined as high risk for the novel coronavirus (as of Sept. 24), they must pass a COVID-19 test within 72 hours before arrival. They then must stay in approved accommodations, and submit to further testing and seven days of monitoring after arrival.

Bermuda: American visitors are permitted if they get a negative result on a PCR COVID-19 test administrated no more than seven days before flying to the island. On arrival, visitors will be tested again at the airport and quarantined in their lodgings until results are back (typically 24 hours).

Bosnia-Herzegovina: Americans are allowed to visit if they can show a negative COVID-19 test (PCR) not older than 48 hours from the moment of entry.

Costa Rica: U.S. visitors are evaluated state by state; the nation has opened its borders to California. It had already opened to residents of 19 other states. Costa Rica also requires visitors to have passed a COVID-19 test less than 48 hours before their travel to the country. Visitors also need medical insurance and a health pass form available online.

Croatia: Since July, Americans have been allowed to visit as long as they can show a negative result from a PCR COVID-19 test administered less than 48 hours before arrival. If you arrive with no test result, you will be ordered to quarantine for seven days and take a PCR test.

Dominica: Because the U.S. is considered a high-risk country, Americans are allowed in only if they answer a health questionnaire and upload and submit COVID-19 test results (PCR) that are no more than 72 hours old. Americans must also submit to a rapid COVID-19 diagnostic test upon arrival. If the result is negative, the visitor is allowed to head to a quarantine facility or government-certified private property for at least five days. After five days on the island, visitors take another COVID-19 test.

Egypt: Americans may enter with a negative COVID-19 test (specifically a PCR and/or serology test) taken no more than 96 hours before their flight (children 6 and younger are exempt). You must show a printed copy of the test. You must show proof of health insurance when you arrive. Also, health screenings are in place at airports and ports.

French Polynesia: Americans may enter with a test, but strict rules are enforced. The region, which includes Tahiti, provides a list of approved and nonapproved RT-PCR tests, which must be taken within three days of your departure date. Also, you must enter the results on an electronic platform. During your stay in Tahiti, you have to test four days after your arrival. Discos and nightclubs are closed, gatherings of more than 10 people aren’t allowed, and strict rules apply to restaurants and bars. You must wear a mask or face a stiff fine.

Honduras: You’ll need a PCR or rapid test to enter the country, and you can expect health screening procedures at the airport and ports. Shopping and other activities are allowed on alternating days, depending on the last digit of your U.S. passport number.

Jamaica: Americans 12 and older must take a COVID-19 test (PCR) that has been approved by specific health officials (antigen and self-test kits won’t be accepted). You must take the test less than 10 days before you visit and apply to enter the country (applications are accepted up to five days — but no later than two days — before your departure).

Quarantines Required

China: Travelers will be screened upon arrival and subject to a 14-day quarantine in “a government-selected facility or hotel at their own expense, with no control over the amenities,” the U.S. Embassy website says. You may be required to use location-tracking apps on your phones to be able to visit some businesses.

United Kingdom: Travelers to England, Scotland, Wales and Northern Ireland (which are parting from the European Union) must file journey and contact details online before they leave home. You’ll also need to self-quarantine to enter (each area may have slightly different requirements).