Brekke Fletcher, CNN

(CNN) -- Once one of the world's most powerful travel documents, the might of the US passport has shriveled under the cloud of coronavirus, with doors slammed shut across the planet to American travelers.

With US coronavirus cases recently passing the three million mark, many nations now view America with trepidation. No matter how much they want those tourism dollars, they're unwilling to take the risk of opening their borders.

Even as restrictions ease up in some places, Americans are still on the danger list. Earlier this month, the European Union omitted the United States from its list of 15 countries whose tourists are permitted to visit.

While most US travelers are staying close to home this summer, preferring short-distance car trips to international air travel, some voyagers won't let a global pandemic curb their travel plans.

And there are still a handful of options.

Most of the Caribbean, for example, is open for US tourists. Other countries -- including Mexico, Maldives and Turkey -- aren't exactly welcoming US travelers with open arms (more like a temperature check and a Covid-19 test), but they are allowing visitors to cross their borders for the first time since coronavirus shut down much of the world.

Whether travel to "open" international destinations is responsible or advisable is up to individuals to decide. But it's worth noting that since the pandemic is ongoing, anything can change at any time.

Also worth noting: The US Centers for Disease Control and Prevention advises against all nonessential international travel.

While there may be bookable international flights to restricted countries, any outbound US passenger should check with the US Embassy and the airline before finalizing travel plans.

Here are the countries where it's still possible for US passport holders to visit.

Albania

Across the Adriatic Sea from Italy, the former communist country of Albania resumed international commercial flights as of June 15.

There are no specific details in terms of what US travelers can expect upon arrival to Albania, however, the US Embassy website states that there will be additional medical personnel at all points of entry, as well as screenings and potential quarantine requirements.

"Travelers should be prepared for travel restrictions to be put into effect with little or no advance notice," it states.

Antigua and Barbuda

As of July 9, US travelers to Antigua and Barbuda "arriving by air must present a negative Covid-19-RT-PCR (real time polymerase chain reaction) test result, taken within seven days of their flight," according a travel advisory on the country's tourism website.

Further to that, visitors are subject to monitoring by local health officials for periods of 14 days and another Covid-19 test may be required while visiting, which could mean quarantining while waiting for the test result.

Masks are required in public spaces and any person violating safety measures could be subject to a $5,000 fine and the possibility of six months imprisonment. Anyone going is advised to read the fine print.

Aruba

US passengers from 24 states, including hotspots such as California and Florida, will be required to upload a negative Covid-19 test result via Aruba's embarkation/disembarkation card process, 72 hours prior to arrival in Aruba.

Travelers arriving from the other 26 states can opt to have a test taken upon arrival, though the test must be prepaid and there is a mandatory quarantine while awaiting test results.

Aruba also requires travelers to be insured so that they are protected from medical expenses should they test positive for coronavirus during their stay.

The Aruba tourism site has all the specific health requirements for incoming passengers, which are both considerable and subject to change, so confirm the latest information prior to booking travel.

The Bahamas

On Monday, July 20, The Bahamas announced it's closing to US tourists, effective July 22. The island nation had just reopened to international travel on July 1.

A news release dated July 19 states, "Due to the continued increase in Covid-19 cases in the United States, as well as an uptick in cases in The Bahamas, Prime Minister, The Most Hon. Dr. Hubert Minnis, has made the difficult decision to close borders to international commercial flights and commercial vessels carrying passengers from the United States. The order is effective as of Wednesday, July 22 at midnight. In addition, Bahamasair will cease outgoing flights to the United States, effective immediately."

Private sea vessels and aircraft from the US are still permitted. Updates on tourism status can be found on their dedicated Covid-19 travel website.

Barbados

The island of Barbados welcomed tourists again on July 12. New protocols to safeguard visitors and residents are in effect, and travelers are now required to complete an online immigration card, which can be done 72 hours before departure and submitted 24 hours before traveling.

The form includes health questions, including whether the traveler has a negative Covid-19 test result.

Travelers can opt to take a Covid-19 PCR test upon arrival, though travelers from the United States who wish for a more seamless travel experience are strongly encouraged to pre-submit their negative test results via the immigration portal and arrive with proof of those results in hand.

Belize

When Belize reopens its airport on August 15, inbound US passengers will have to have downloaded the new Belize Health App (not currently operational) and supply the required details before boarding a flight to Belize.

The app provides travelers with an identification and QR code that will be used for contact tracing while in country. The app will check in daily to confirm visitors do not have symptoms.

Visitors should book hotels that have received Belize Tourism's "gold standard certificate of recognition." Only those hotels will be open as of August 15 and guests will be screened before checking in.

Belize also encourages visitors to take a Covid-19 PCR test at least 72 hours before travel and to present negative results in order to fast-track entry.

It's advised to check the Belize Toursim Board website for updates.

Bermuda

Welcoming visitors since July 1, Bermuda requires each inbound passenger (regardless of age) to apply for travel authorization, at the cost of $75 per adult and $30 for flight crew and children aged nine and under.

Visitors who do not have a negative Covid-19 PCR test result will not be given authorization to travel to Bermuda.

Upon arrival, passengers must present the pre-departure negative test results, submit to an additional Covid-19 test and quarantine in their accommodation until the results are ready, which takes between six and eight hours.

Additional testing is required after day three, seven and 14, depending on the length of stay, at various testing sites around the island.

The fee for the travel authorization covers the cost of testing.

Cambodia

If you're sitting on $3,000 and want to fly to Phnom Penh International Airport to embark on a Cambodian adventure, this is now an option.

In a June 10 statement, the airport's director, Sao Wathana, announced, "Upon arrival, all foreign passengers are required to deposit $3,000 at the airport to pay for the virus prevention services."

Visitors will be required to take a Covid-19 test, and if negative, the remaining funds will be returned minus $160 to cover the cost of the test and a fully catered day in a waiting center.

A positive test result carries serious financial and social consequences, involving hospitalization and medical care, and the 14-day quarantine of all fellow inbound flight passengers and additional affiliated expenses.

Details can be found on the Tourism Cambodia website.

Croatia

Ignoring the EU ban Americans traveling to Europe, Croatia began welcoming US tourists on July 10.

Travelers need to present a negative Covid-19 PCR test,"not older than 48 hours (starting from the time of taking the swab until arrival at the border crossing)," according to an alert on the website of the US Embassy in Zagreb.

Dominican Republic

As part of the standard immigration and customs forms, US passengers traveling to the Dominican Republic will have to fill out a Health Affidavit to confirm they have not had any coronavirus symptoms within 72 hours of travel.

However, anyone presenting symptoms or registering a temperature above 100.6 F (38 C) will have to be tested. Passengers who test positive will be isolated and treated.

Visitors also need to provide contact information, but the gist is that when it comes to Covid-19 symptoms and testing, the DR is willing to take your word for it.

Dubai

Dubai resumed tourism on July 7. Visitors to the UAE are required to have medical travel insurance to cover any necessary Covid-19 treatment and present a negative Covid-19 PCR test result within 96 hours of arrival.

Travelers must complete a "health declaration form" before departing to confirm they are not experiencing any coronavirus symptoms.

Passengers can expect temperature checks and mandatory testing if they display symptoms.

Furthermore, "tourists are required to register all their details in the COVID-19 DXB app on arrival," according to the Visit Dubai website.

Ecuador

Unless you have an extra 14 days to burn, Ecuador is not a great international option. Though US travelers are allowed to go, they are subject to a mandatory 14-day quarantine -- even with a negative Covid-19 PCR test result.

Quarantine for foreigners is at their expense and only available at specified hotels in Quito, Guayaquil or Manta, and those reservations must be confirmed before arrival.

The Galapagos islands' tourist sites reopened to visitors on July 13, though at present, with the quarantine rule is in effect, a visit to the UNESCO heritage site is a major time investment.

Egypt

Egypt relaxed restrictions on tourism July 1, and there are regular direct flights on EgyptAir from New York City and Washington, DC, to Cairo.

US travelers need to procure a visa either before travel or upon arrival and will be subject to temperature checks and must adhere to social distancing and mask-wearing requirements.

In terms of precisely what awaits US passport holders upon arrival, details are hard to come by. Coming prepared with a negative Covid-19 test result that is at most 48-hours old and proof of medical insurance is advisable

Egypt announced it was resuming many tourist operations, including the opening of the Giza pyramids on July 7.

French Polynesia

Travelers seeking the ultimate in tropical isolation are welcome to the islands of Tahiti and Bora Bora on July 15.

French Polynesia requires a negative Covid-19 test within 72 hours of departure, to be presented before travelers board their flight.

Passengers must also complete a "sanitary entry form" (one per family), detailing their current state of health and agree to report symptoms and submit to additional testing should it be deemed necessary upon arrival or during the stay.

Jamaica

Jamaica reopened to tourists on June 15, but has since updated its requirements for travelers, which include the completion of an online "travel authorization" and the possibility of being tested upon arrival.

As of July 15, due to the increase in coronavirus cases in the United States, passengers arriving from New York, Florida, Arizona and Texas are required to upload negative Covid-19 test results to receive travel authorization. The test date must be within 10 days of arrival.

Each passenger must present the travel authorization along with their passport at the point of departure.

All travelers "from areas where there is high community transmission of the virus" will be tested at the airport upon arrival and required to quarantine in their chosen accommodations until the results are ready, usually within 48 hours.

Only hotels, villas or guesthouses within the "resilient corridor" are accepting guests. According to Visit Jamaica, "the resilient corridor includes the coastline from Negril to Port Antonio. Only businesses within the corridor that have been trained and assessed for adherence to Covid-19 protocols are allowed to open to tourists."

Kosovo

No testing or quarantine is required for travelers arriving in Kosovo.

According to the US Embassy Kosovo website: "The Pristina International Airport is reportedly open to all travelers; however, some US citizens continue to be denied boarding in the US because they cannot prove they are residents or citizens of Kosovo.

"Despite being open to tourists, the Embassy strongly suggests US visitors cancel or postpone any travel plans to Kosovo this summer."

The Maldives

One of the world's most desirable holiday destinations, the Maldives is reopening to all international tourists on July 15. US travelers are not required to be tested prior to departure, but will need to complete a health declaration upon arrival.

All tourists must have booked their accommodations in advance.

According to a press release from Visit Maldives: "Tourist resorts, liveaboard vessels and hotels located on uninhabited islands are open for bookings starting from July 15. Guest houses and hotels located on inhabited islands will open for bookings starting from August 1."

Mexico

Though the land border between the United States and Mexico remains closed, US travelers can fly to Mexico.

No testing requirements are currently in place, although Mexico's recent reopening has coincided with increased cases of coronavirus.

Travelers can expect temperature checks and other additional screenings upon arrival.

North Macedonia

North Macedonia is open for tourists. There are no test or quarantine requirements, but airports are conducting thermal screening for all passengers.

Rwanda

Rwanda's national parks make it one of the most desirable destinations in Africa, but currently only if you can afford a private charter to get there.

If you can hold on a few weeks, Rwanda will reopen to international commercial flights on August 1. At that time all international visitors must present a negative Covid-19 PCR test, taken within 72 hours of arriving in Rwanda.

Any tourists who wish to visit attractions like the Volcanoes National Park must take an additional Covid-19 test at the airport, and expect to quarantine in their hotel until the results are ready.

Serbia

Serbia's borders are open, but tourists should be aware of a recent spate of protests around new restrictions, including a weekend long curfew. There has also been a recent spike in coronavirus cases in the country.

St. Barts

The island of St. Barts reopened to international travelers in late June. As of July 10 visitors are required to show a negative Covid-19 PCR test result, taken within 72 hours of arrival.

Those staying longer than a week will need to pay about $150 for an additional test on their eighth day.

Currently, travelers can get to St. Barts via Antigua and San Juan, Puerto Rico. Both airports require the same documentation: a negative Covid-19 PCR test result, taken within 72 hours of arrival.

St. Maarten Princess Juliana Airport remains closed to commercial flights from the US.

St. Lucia

Those traveling to St. Lucia from the United States are required to provide a negative result from a Covid-19 PCR test, taken within seven days of travel. Visitors must also complete a Pre-Arrival Registration form -- and travel with a printed, completed form.

Visitors must have confirmed reservations at a Covid-certified property (currently there are seven) for the duration of their trip. And tourists must stay where they have registered, unless the hotel has coordinated an approved excursion.

St. Vincent and the Grenadines

All travelers to St. Vincent and the Grenadines must take a Covid-19 PCR test upon arrival, unless they arrive with a negative Covid-19 test result (antibody test within five days, PCR test within two days), in which case they will not be required to quarantine.

Visitors must be granted "VINCYCOVID App*Approval" and complete the "VINCYCOVID questionnaire."

In addition, all passengers will be screened for symptoms upon arrival, including temperature checks.

Tanzania

Another instance where travel is not forbidden, Tanzania is officially open to tourists. While there are no testing or quarantine requirements in place, travelers will be subject to extensive screenings and in some cases, will be required to take a Covid-19 test.

Incoming passengers are required to fill out a "health surveillance form" upon arrival.

Turkey

The majority of Turkey's borders have been open since June 12. There are currently no restrictions for US citizens traveling to Turkey, although passengers must complete an information form and prepare to be checked for coronavirus symptoms upon arrival.

In addition, the US Embassy and Consulates in Turkey stipulates that all US citizens must purchase tickets for onward travel to the United States.

Turks and Caicos

The most recent information related to US travelers who wish to visit Turks and Caicos is as follows:

As of July 22, visitors must provide a negative Covid-19 test result and the test must have been taken within five days of arrival. Children 10 and under are not bound to this requirement.

Travelers must also complete an online health screening questionnaire and carry travel medical insurance to cover any Covid-19-related costs (from quarantine to hospital care).

Ukraine

The US is considered a "red zone" country in Ukraine, meaning it has more than 40 active coronavirus cases per 100,000 people. To gain entry to Ukraine, passengers should download the "Dii Vdoma" app and choose one of three options.

They can either take a Covid-19 PCR test within 24 hours of crossing the border, enter an isolation unit, or quarantine at their destination, which they can register via the app.

There more details on official Visit Ukraine Today website.

Travel health insurance is also a requirement, to cover any costs related the treatment of Covid-19.

United Kingdom

US travelers have always been allowed to travel to the United Kingdom -- they just have to submit to a mandatory, 14-day quarantine.