This article originally appeared in Travel+Leisure.

All international travelers will soon be required to arrive in the United States with a negative COVID-19 test, according to new guidance from the U.S. Centers for Disease Control and Prevention released Tuesday.

Under the new rules, travelers flying to America would have to show proof of a negative viral test before boarding their flight. The test must be taken within three days of their scheduled departure and passengers will have to show written documentation to the airline. Alternatively, passengers can provide proof they have recovered from COVID-19.

The new rule will go into effect on Jan. 26.