Canada on Monday is lifting its prohibition on Americans crossing the border to shop, vacation or visit, but the United States is keeping similar restrictions in place for Canadians, part of a bumpy return to normalcy from Covid-19 travel bans.

U.S. citizens and legal permanent 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. Travelers also must fill out a detailed application before crossing.

Even though travelers have to register, the Canada Border Services Agency won’t say how many people they are expecting to enter Canada for the reopening. But travelers should plan for the possibility of additional processing time at the border.

“CBSA will not compromise the health and safety of Canadians for the sake of border wait times,” agency spokeswoman Rebecca Purdy said in a statement.

Garnet Health, an Essex, Vermont-based company that offers same-day COVID-19 testing, has seen the number of tests it performs more than triple in recent weeks. The increase coincides with Canada’s decision last month to drop a two-week quarantine requirement for its citizens when they return home from the U.S.

“I imagine once that border opens, we are going to see lots of people,” said Chelsea Sweeney, the company’s director of business development.

The U.S.-Canada border has been closed to nonessential travel since March 2020 to try to slow the spread of the coronavirus.

The U.S. has said it will extend its closure to all Canadians making nonessential trips until at least Aug. 21, which also applies to the Mexican border. But the Biden administration is beginning to make plans for a phased reopening. The main requirement would be that nearly all foreign visitors to the U.S. will have to be vaccinated against the coronavirus.

But Canadians aren’t waiting for reciprocal rules.

Joel Villanueva, owner of Primo’s Mexican Grill in White Rock, British Columbia, about 2.5 miles (4 kilometers) north of the U.S. border, is more than ready for Americans to return. “Let’s get this thing going,” he said. “A lot of our customers are from the United States, and we are literally minutes from across the border. We welcome our Americans, and we depend on their foot traffic.”

(With AP inputs)