Canada lifted its prohibition on Americans crossing the border to shop, vacation or visit on Monday while the United States is maintaining similar restrictions for Canadians, part of a bumpy return to normalcy from COVID-19 travel bans.

U.S. citizens and legal residents must be both fully vaccinated and test negative for COVID-19 within three days to get across one of the world’s longest and busiest land borders, and Canadian officials warn they won’t sacrifice safety for shorter border waits. Travelers also must fill out a detailed application on the arriveCAN app before crossing.