The White House announced Monday that the United States will start allowing foreign travelers from dozens of countries, including the United Kingdom, China, and nations of the European Union, as long as they are vaccinated against the coronavirus.

The move, which is great news for airlines, will ease travel ban rules put in place early in the pandemic. Since the widespread distribution of effective vaccines, many nations of the E.U. have welcomed tourists from the U.S., but the U.S. has been hesitant to set the same travel policies.

Under the new policy, the U.S. will admit fully vaccinated travelers flying from the 26 E.U. countries in Europe including France, Germany, Italy, Spain, Switzerland and Greece, as well as Britain, Ireland, China, India, South Africa, Iran and Brazil. Previously, the U.S. has barred non-U.S. citizens who were in those countries within the past 14 days.

White House COVID-19 coordinator Jeff Zients said during a press conference on Monday that foreign travelers will need to provide proof of vaccine before boarding, as well as proof of a negative COVID test taken within three days of their flight.

"We know vaccines are effective, including against the Delta variant, and vaccines are the best line of defense against COVID, so this vaccination requirement deploys the best tool we have in our arsenal to keep people safe and prevent the spread of the virus," Zients told reporters.

Additionally, unvaccinated Americans who plan to travel outside the U.S. will be required to show proof of negative COVID test within a day prior to their departure, as well as their return to the U.S.

"In the coming weeks, [the Centers for Disease Control and Prevention] will be issuing a contact tracing order requiring airlines to collect currency information for each U.S.-bound traveler, including their phone number and email address," Zients added.

Moving forward, attention now shifts to what vaccine(s) will be recognized as acceptable for travelers by the U.S. under the policy change. The U.S. has fully approved the Pfizer (PFE  )-BioNTech (BNTX  ) vaccine for general public use, and has issued emergency use authorizations for both the Moderna (MRNA  ) and Johnson & Johnson (JNJ  ) shots.