But the US for now has placed most of Europe under a Level 4: Do Not Travel advisory.
More travel could open up in 2021 as a result of the vaccine rollout.
The European Union is set to allow visitors from the US this summer -- as long as they've been fully vaccinated against COVID-19, The New York Times reported Sunday. The report cited an interview with Ursula von der Leyen, president of the European Commission.
"All 27 member states will accept, unconditionally, all those who are vaccinated with vaccines that are approved by EMA," von der Leyen told the Times without mentioning a specific timeline. This includes the Pfizer, Moderna and Johnson & Johnson vaccines.
Read more: Vaccine passports for COVID-19: How they'll be a part of global travel
However, except for Iceland, most of Europe is now under a Level 4: Do Not Travel warning in the US after travel advisories were updated last week to better reflect current COVID-19 health notices from the CDC. Iceland -- which isn't part of the EU -- notes on its travel website that to be allowed into the country, you will need a vaccination certificate showing you've received shots from Pfizer, Moderna, AstraZeneca or Janssen/Johnson & Johnson.
The UK, which left the EU last year, is currently allowing visitors from the US as long as you provide proof of a negative coronavirus test or documentation showing you recovered from COVID-19 in the last 90 days. You'll also have to quarantine for 10 days after arrival and get two coronavirus tests during this time, both of which you must book before traveling. The UK is on the US' Level 4 advisory warning, though.
The countries that have lower-level warnings for travelers from the US include Pacific nations like Australia, New Zealand and Fiji; Southeast Asian countries like Thailand, Vietnam, Laos and Singapore; some African nations including Ghana, Nigeria and Morocco; and Asian giants China, Hong Kong, Japan and South Korea.