For more than 16 months, the U.S. and Canada turned away tourists at entry points across the 5,500-mile land border in an effort to contain further spread of Covid-19. On Monday, Aug. 9, Canada began allowing fully vaccinated Americans to enter the country again. The U.S. didn’t reciprocate. Last month, it extended its land border restrictions with Canada and Mexico.

Can you visit Canada now?

If you’re a fully vaccinated American citizen or a green-card holder living in the U.S., the answer is likely yes. Beginning Aug. 9, fully vaccinated Americans who meet other Canadian government criteria can enter Canada for nonessential purposes such as tourism and recreation.

Travelers need to wait at least two weeks after their last vaccine dose before crossing the border, and they must present proof of an approved, negative Covid-19 test taken during 72 hours before their arrival in Canada. They also can’t have any symptoms of the disease when they arrive at the border.

Canadian Prime Minister Justin Trudeau said last month that the decision to reopen to fully vaccinated Americans was “in recognition of our unique bond, especially between border communities.” He said Canada plans to allow fully vaccinated tourists from other countries to visit beginning Sept. 7.

Canada also allows its own citizens or permanent residents to enter the country, and essential workers—most notably truck drivers—have been allowed to cross the border throughout the pandemic, as both countries agreed that trade of goods and services wouldn’t be affected.

What documents do I need to travel to Canada?

Travelers need to upload proof of their vaccination to a Canadian government app or website called ArriveCAN before they board a flight or reach a land crossing, and carry a paper or digital copy of their proof of vaccination with them. Those who meet all the government’s requirements won’t have to quarantine, although officials said everyone is expected to have a quarantine plan in case a border official determines they don’t meet all requirements.

Proof of a negative Covid-19 test is also a requirement, and must be administered during the three days before arrival in Canada. Canada generally accepts molecular Covid-19 tests, which look for the virus’s genetic material, such as polymerase chain-reaction tests. It doesn’t accept antigen tests, which look for viral proteins.

Do I need to be fully vaccinated to cross the border?

If you’re traveling for nonessential reasons, such as tourism or to visit a property in Canada, you need to be fully vaccinated with an accepted Covid-19 vaccine or a combination of two different accepted vaccines. Canada accepts vaccines from Pfizer Inc. and partner BioNTech SE, Moderna Inc., Johnson & Johnson and AstraZeneca PLC. Travelers must have waited at least two weeks from the date of their last vaccine dose before crossing the border and they must upload proof of their vaccination status in advance.

Fully vaccinated Americans are permitted to bring unvaccinated children under 12 years of age to Canada, although those children won’t be allowed in group settings like camps or day-care centers.

What are the current Covid-19 restrictions in Canada?

Restrictions in Canada vary across the country’s 10 different provinces and three territories. Some provinces, most notably Alberta, have dropped nearly all restrictions. Others, such as Ontario, have rules regarding use of masks indoors and capacity limits for museums, movie theaters and other performing-arts venues.

The Centers for Disease Control and Prevention in June downgraded its warning about travel to Canada by one level, from “very high” to “high,” coinciding with a steep drop in Covid-19 cases in Canada after a destabilizing third wave of infections. The third wave prompted authorities in Canada to impose strict economic and social-distancing restrictions. However, nearly all Canadian regions have relaxed those restrictions, at least in part, based on vaccination rates and a sharp drop in infections. By Aug. 8, about 62% of Canadians were fully vaccinated, compared with 50% of Americans.

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Despite Canada’s high vaccination rate, public-health officials warned on July 30 that the country could be at the beginning of a fourth wave of Covid-19 infections driven by the more transmissible Delta variant of the virus. Case counts in Canada have climbed in recent weeks but remain almost 90% lower than they were during the country’s third-wave peak in April and well below the level in the U.S. on a per-capita basis.

Can Canadians enter the U.S.?

The U.S. Department of Homeland Security last month extended its border restrictions with Canada and Mexico through Aug. 21. That means Canadians still can’t cross at the land border unless their travel is considered essential.

U.S. officials have told their Canadian counterparts that they want to improve the U.S. vaccination rate before opening the land border, according to officials in both countries. White House press secretary Jen Psaki said last month that the Biden administration would like to see a return to international travel, both for tourism and to allow families to reunite, “but we rely on public health and medical advice” to determine when to make changes.

Despite restrictions at the land border, Canadians are allowed to fly into the U.S., regardless of their vaccination status, if they present proof of a negative Covid-19 test administered during the three days before their travel.

Officials in Canada have played down the difference in reopening plans, saying each country needs to rely on its own experts to determine when and how to reopen. Kirsten Hillman, Canada’s ambassador to the U.S., said at a July 23 event hosted by the Wilson Center that there continues to be “an enormous amount of information sharing” between the two countries. However, she added, “coordination doesn’t mean you’re going to do exactly the same thing.”

—Michelle Hackman contributed to this article.

Write to Paul Vieira at paul.vieira@wsj.com and Kim Mackrael at kim.mackrael@wsj.com