Editor's Note — CNN Travel updates this article periodically. It was last updated in its entirety on June 15. Entries on Austria, Belgium, Czech Republic, Estonia, Germany, Latvia, Liechtenstein, Lithuania, Netherlands, Poland, Saudi Arabia, Slovenia and Switzerland were added on June 29.
(CNN) — US passport holders have more international travel options now than at any point during the Covid-19 pandemic.
Total US cases are nearing the 33.6 million mark since the pandemic started, but the rate of new cases has been slowing down recently. The United States is one of the world leaders in vaccination rates and has been leading among nations with a population over 100 million. But we're not out of the woods -- the US Centers for Disease Control and Prevention said June 15 that the Delta variant of the novel coronavirus, also known as B.1.617.2, is a "variant of concern."
Still, more and more of Europe is opening up to US leisure travelers in time for summer -- especially the fully vaccinated. Germany and Austria are just two of the latest to open their doors. The global situation is in flux, though. Even as some places reopen for the first time, others are closing back up.
In the end, it's up to you to decide whether travel to international destinations is a good idea. The health risks are obvious if you're not fully vaccinated. Nations might change their rules at any time. You may have to adhere to strict curfews and mask mandates. Violations could involve big fines and even jail time.
If you want expert input into your decision, the US State Department and the CDC provide Covid-19 risk assessments by country. Both agencies rate many of the countries open to US travelers at Level 4, the highest risk for Covid-19. Also, remember that all air passengers 2 and older must show proof of a negative Covid-19 test that's no more than three days old to enter the United States.
What follows is an alphabetical list of countries and territories where it's still possible for US passport holders to go for a vacation. Click the links we've provided for very important information on:
-- Presenting negative results from Covid-19 tests to enter (including time limits to take the test, types of tests allowed and additional tests upon arrival).
-- Quarantines (if any) and health screenings.
-- Possible exemptions from the rules for the fully vaccinated or people recovered from a recent case of Covid-19.
-- Health insurance requirements, curfews and lockdowns.
These are all things you need to research before you book your trip. People testing positive for Covid-19 upon arrival or while visiting can expect to go into quarantine. Rules for land entry may be different.
Blessed with a gorgeous Adriatic Sea coastline, this southeastern European country has no test requirements or quarantine. Details and updates: US Embassy.
US visitors will once again have access to the tropical waters of Anguilla.
Courtesy Belmond Cap Juluca
Antigua and Barbuda
This independent nation in the eastern Caribbean, known for sheltered bays and historical sites, is open. Testing and quarantine requirements are in place. Details and updates: US Embassy | Antigua and Barbuda government website.
From the historic capital of Yerevan to wild national parks, Armenia is open to US tourists. Testing required; quarantines in some circumstances. Details and updates: US Embassy | Armenia's official Covid-19 travel website.
Scroll down to the Dutch Caribbean entry below for information on Aruba and other islands in this group.
US citizens can now visit this Alpine nation renowned for its culture and food. You must have negative Covid-19 test or proof of vaccination or proof of past infection to enter. No quarantine in place. Details and updates: US Embassy | Austria Entry Requirements.
Off the coast of Florida, this large chain of islands is loved for its many beaches. Testing required; exemptions for the fully vaccinated. No quarantine in place. Details and updates: US Embassy | Bahamas travel website | Bahamas Travel Health Visa.
This populous South Asian nation offers beaches, interesting architecture and cultural experiences. Testing and quarantine requirements are in place. Details and updates: US Embassy.
Bruges is a popular destination for tourists in Belgium.
Emmanuel Dunand/AFP/Getty Images
Home to historic Bruges and busy Brussels, Belgium is now open. No testing required for citizens of the US, currently labeled as an "orange zone" nation; no quarantine unless arriving from a "red zone" nation. Details and updates: US Embassy | Belgium Embassy | Belgium color codes for nations | Passenger Locator Form
English is spoken in this Central American nation filled with wildlife spotting opportunities and stunning barrier reefs. Testing required; fully vaccinated exempt. No quarantine in place. Details and updates: US Embassy | Belize Tourism Board.
This landlocked South American country offers surreal landscapes from Andean to jungle. Testing and quarantine requirements in place. Details and updates: US Embassy.
Bosnia and Herzegovina
Botswana is renowned for its safari opportunities. Elephants are always a top sighting on any excursion.
This southern African nation is famed for its wildlife in the Okavango Delta and elsewhere. Testing and quarantine requirements are in place. Details and updates: US Embassy.
South America's largest country has the lure of Rio's party atmosphere and the Amazon River's mystique. It also has a very high daily number of Covid-19 cases. Testing required; quarantines are not. Details and updates: US Embassy | Health declaration.
British Virgin Islands
This pretty island group lies just to the east of the US Virgin Islands in the Caribbean. Testing and quarantine requirements are in place. Details and updates: US Embassy | BVI government website | BVI Gateway website.
Historic towns and natural landscapes are Bulgaria's calling cards. Testing required; exemptions for fully vaccinated or recovered from Covid-19 infection. No quarantine. Details and updates: US Embassy.
Downtown Medellin is a great place to take a stroll and soak up urban Colombian atmosphere.
Côte d'Ivoire (Ivory Coast)
Côte d'Ivoire is a popular destination for people wanting to enjoy West African culture and food. Testing required; quarantine encouraged but not required. Details and updates: US Embassy | Travel declaration and fee.
Croatia, the jewel of the Adriatic, is once again open to US leisure travelers. Testing required to enter; exemptions for the fully vaccinated or recovered from Covid-19 infection. No standard quarantine in place. Details and updates: US Embassy | Croatia official entry form.
Both parts of this politically divided Mediterranean island are open to US tourists. The Republic of Cyprus and the northern third of the island administered by Turkish Cypriots (Turkish Republic of Northern Cyprus) each have their own rules of entry and testing. Details and updates: US Embassy in Nicosia | Visit Cyprus.
Prague's timeless charm makes it one of Central Europe's most popular destinations.
Sean Gallup/Getty Images
Scroll down to the United Arab Emirates entry below.
Dutch Caribbean islands
Find out the important details on these various Dutch islands in the Caribbean -- renowned for their hospitality and ocean life -- by clicking on the links:
Saba: Known more for its rugged landscape and hiking than beaches, little Saba is open. Testing required. Quarantine in place; exemption for fully vaccinated. Details and updates: Saba Tourism | Saba EHAS application.
The animals of the Galapogos Islands, part of Ecuardor, fascinate scientists and tourists alike.
PABLO COZZAGLIO/AFP via Getty Images
This Andean country at the equator also owns the Galápagos Islands in the Pacific. Testing required; fully vaccinated exempted. Quarantine required in some circumstances. Details and updates: US Embassy.
The Nile River nation has been attracting people to see its wonders for many centuries. Testing required; quarantine is not. Details and updates: US Embassy.
Ethiopia has a unique and ancient culture and rugged, otherworldly landscapes. Testing and quarantine requirements are in place. Before you travel there, closely monitor news reports about violence in the northern Tigray region (video) on the border with Eritrea. Details and updates: US Embassy.
French Polynesia is the idealized South Pacific destination. Testing required; quarantine in place with an exemption for the fully vaccinated. Details and updates: Islands of Tahiti | FAQ document | Online ETIS form.
Georgia is a geographical and cultural crossroads at the Caucasus Mountains. Testing required unless you're fully vaccinated. No self-isolation for the unvaccinated under certain conditions. Details and updates: US Embassy | Georgian Ministry of Foreign Affairs.
Frankfurt, a financial and modern powerhouse of Germany, also has plenty of Old World charm, making it the perfect city for travelers who want a little bit of everything.
Boris Roessler/AFP/Getty Images
From edgy Berlin to picturesque Bavaria, Germany is now open. Testing required; quarantine depends on vaccination status and nation from which you've arrived. Details and updates: US Embassy | German Missions in the US
This West African cultural jewel offers historical sites, delicious food and surfing. Testing required. No quarantine. Details and updates: US Embassy.
Greece, with its many ancient ruins and islands, is now open to US travelers. Testing required; exception for the fully vaccinated. No quarantine. Details and updates: US Embassy | Passenger locator form.
This Central American country offers historical sites and stunning volcano landscapes. Testing required; exceptions for the fully vaccinated or those fully recovered from Covid-19. No quarantine. Details and updates: US Embassy | Online health pass.
Honduras has epic diving off Roatan Island and other locations. Testing required; fully vaccinated travelers are exempt. Conditional quarantine in some circumstances. Details and updates: US Embassy | Online precheck form.
Geysers, glaciers, hot springs and waterfalls await in Iceland. You must be fully vaccinated or have proof of recovery from Covid-19 to enter. Testing and quarantine requirements in place as well. Details and updates: US Embassy | Iceland travel registration.
Great Blasket Island is a hiker's paradise -- and the donkeys seem to like it, too.
Courtesy Tourism Ireland
From ancient Jerusalem to modern Tel Aviv, Israel now allows US tourists. Testing required. Quarantine in place for those not fully vaccinated or recovered from a case of Covid-19. You should keep a close watch on developments as you plan your trip regarding the recent conflict between Israel and Gaza. Details and updates: US Embassy | Israel Ministry of Health.
A visit to Jordan's ancient city of Petra is a travel highlight not only of the Arab nation but of the entire world.
KHALIL MAZRAAWI/afp/AFP via Getty Images
Home to the amazing ruins of Petra, Dead Sea coastline and the dazzling landscape of the Wadi Rum, Jordan is open to US vacationers. Testing required; quarantine is not. Details and updates: US Embassy.
Latvia -- with a walkable capital city, Art Nouveau architecture and surprising wildlife -- is open. Testing required; quarantine is not. Details and updates: US Embassy.
This tiny nation is open. Scroll to the Switzerland entry below for details.
This Baltic nation is made for history buffs and is open to fully vaccinated Americans only. No testing or quarantine. Details and updates: US Embassy.
The land border between the US and Mexico remains closed through at least June 21, but US travelers can still fly there. No testing or quarantine requirements are in place. The US State Department lists numerous states to avoid because of crime. Details and updates: US Embassy.
US jet-setters can visit the Mediterranean city-state if they are fully vaccinated. Testing also required. Details and updates: Embassy of Monaco.
This Balkan nation is allowing US travelers. Testing under most circumstances required; exceptions for the fully vaccinated or the naturally immune because of previous Covid-19 illness. Details and updates: US Embassy | Institute of Public Health of Montenegro.
Starting June 15, this North African favorite is open leisure travelers from the United States without special invitations. Testing required, but no quarantines in place. Details and updates: US Embassy | Visit Morocco.
US citizens can visit this southern African desert nation that appeals to adventure travelers. Testing required; quarantine is not. Details and updates: US Embassy.
US travelers can visit the landlocked Himalayan nation. Testing and quarantine requirements in place, regardless of vaccination status. Details and updates: US Embassy.
US travelers can now visit Amsterdam and the rest of the Netherlands. No testing or quarantine is required as the US is deemed a safe country. Details and updates: US Embassy | Government of Netherlands
The Cathedral of Granada is a popular site.
US passport holders can now see Krakow and Poland's other wonders. No testing is required, but quarantine is. Details and updates: US Embassy.
US travelers now have a travel window to get their Lisbon fix.
Courtesy Jessica Yubas
Portugal is open to US citizens from June 15 to 27. The measure will be reviewed every two weeks and unless renewed expires midnight on June 27. Testing is required; quarantine is a possibility. Details and updates: US Embassy.
Romania offers mystique, wooded and mountainous landscapes and lots of history. No testing required. Quarantine in place with exceptions for fully vaccinated and those recovered from Covid-19. Details and updates: US Embassy | Romanian Embassy.
Senegal, known for its West African beaches and music, welcomes US tourists. Testing is required; no quarantine in place. Details and updates: US Embassy.
Serbia features noteworthy architecture. City Hall is in the city of Subotica in the far north of the country, near the border with Hungary.
Serbia is steeped in historical sites and dramatic Eastern European scenery. Testing is required but quarantines are not. Details and updates: US Embassy.
This European nation of gorgeous lakes is open only to the fully vaccinated or those recovered from Covid-19. No testing or quarantine required. Details and updates: US Embassy.
With superb national parks, wineries and the allure of Cape Town, one of the most popular destinations in Africa is open. Testing is required; quarantine is not. Be aware some nations aren't allowing entry to tourists who have recently been to South Africa. Details and updates: US Embassy.
After an extended closure, this French island is allowing fully vaccinated travelers from the United States. Testing required. Details and updates: St. Barts entry protocols
St. Kitts and Nevis
This Caribbean escape allows only fully vaccinated tourists to visit. Exemptions are in place for children 17 and younger traveling with vaccinated parents. Details and updates: US Embassy | St. Kitts Tourism | Travel authorization form.
Home of the steep and towering Pitons, waterfalls and volcanic beaches, the independent Caribbean nation of St. Lucia is open. Testing and quarantine requirements are in place. Details and updates: US Embassy | St. Lucia travel website.
St. Vincent and the Grenadines
The country's famed Alps are once again open to Americans. Testing required with exemptions for the fully vaccinated or those recovered from Covid-19. Details and updates: US Embassy | Swiss Travel Check.
Kilimanjaro's glaciers could become a thing of the past as average global temperatures rise.
Sergey Pesterev/Flickr Open/Getty Images/Flickr Open
US passport holders can again visit this fascinating Southeast Asian destination famed for its beautiful beaches and spicy cuisine. Testing and quarantine requirements are in place. Details and updates: US Embassy | Royal Thai Embassy | Certificate of entry.
Tunisia offers ancient ruins, desert scenery and sunny Mediterranean beaches. Testing and quarantine requirements in place. Fully vaccinated visitors are exempt from both. Details and updates: US Embassy | Online questionnaire.
Turks and Caicos
This British overseas territory northeast of Cuba and southeast of the Bahamas is known for it coral reefs, ripsaw music and low-key vibe. Testing is required; quarantine is not. Details and updates: US Embassy | Visit Turks and Caicos | Travel authorization form.
Visitors with a respectful approach and careful eye might see a giant gorilla munching shoots and leaves.
This lush nation in Central Africa offers gorilla trekking, Nile River rafting and beautiful lakes. Testing required; quarantine is not. Details and updates: US Embassy.
United Arab Emirates
The UAE, with its glittering towers and luxury resorts, has emerged as a major world destination in the 21st century. Testing required. Quarantine protocols depend on the emirate. Details and updates: US Embassy.
Leisure travel to the UK is highly discouraged but not banned. Testing and quarantine requirements are in place. Rules may vary between England, Scotland, Wales and Northern Ireland. Details and updates: US Embassy | UK government | Declaration form.
Known for Victoria Falls and wildlife, Zambia is allowing visitors. Testing and quarantine requirements are in place. Details and updates: US Embassy.
Recently removed from the open list
The following countries had been allowing US citizens to enter but have closed again or were removed by CNN Travel for other reasons:
-- Cambodia: The US Embassy reports the Southeast Asian nation has stopped issuing tourist visas; you can still apply for business-linked visas.
-- Chile: It has closed its borders to almost all tourists through June 30.
-- Sri Lanka: No international flights allowed until June 1.
This is a curated list and not a full listing. CNN Travel has omitted certain open countries if they had very limited numbers of US travelers before the pandemic; have ongoing or recent armed conflicts, terrorism or rampant crime and unrest; or have entry requirements so extensive and complicated that they put the country out of reach of almost all US citizens. However, you can click here to check for the status and entry requirements of any country or territory in the world you wish to visit.