Cities were big destinations for tourists over the recent Memorial Day holiday weekend. But while domestic tourists are back in places like Las Vegas, the number of visitors coming from outside of the U.S. is not quite 80% of what it was in 2019, according to the International Trade Administration. So what’s holding these international travelers back?

This slow return of foreign visitors tracks with what Kenneth Lippman is seeing on the Segway and e-bike tours he runs in Los Angeles, San Diego and Las Vegas. But that’s a whole lot better than a couple years ago.

“Our international business was nil. It really dropped off of a cliff,” he said.

Now, his customer base of Brits, Canadians and Australians are coming back. Still, even when travel restrictions started lifting, “it wasn’t the very next day that people were traveling,” he said. “It’s still taking time for them to plan their itineraries.”

Getting a visa to the U.S. (if you need one) is also taking time, noted Geoff Freeman, president and CEO of the U.S. Travel Association.

“Current wait times in places like Brazil, India, Mexico, Colombia are 500 days or more just to get an interview at a U.S. consulate,” he said.

While the State Department has stepped up efforts to bring those times down, Freeman said the backlog is leading deep-pocketed international tourists to take their money elsewhere.

“The truth is that other countries around the world are aggressively competing to attract those travelers,” he said.

It also hasn’t been all that long since countries like China and Japan dropped COVID-19 restrictions, said Alex Dichter, head of the global travel practice at McKinsey & Co.

“You don’t take two years, and in some cases three years, of deferred travel plans and execute them all, you know, over the course of a single year,” he said.

That could mean a period of “revenge travel” from international visitors.