The three teenage boys printed directions for what Google Maps said would be a hike of more than five hours through the backcountry of the Howe Sound Crest Trail in British Columbia, Canada.

In reality, their hike weeks ago lasted at least 12 hours and required the intervention of rescue crews, according to the Lions Bay Search and Rescue team.

The trail offers stunning views of a sparkling lake atop craggy mountains. It also features peaks and valleys filled with loose rocks, according to the rescue team. But it involves climbing through more than 4,200 feet of irregular, mountainous terrain.

Expecting to complete that hike in five hours, the rescuers said, was “wildly optimistic.”

Eventually, the three hikers, identified only as two 17-year-olds and an 18-year-old man, ran into trouble. The 18-year-old slipped on a rock and fell about 9 feet, the rescuers said, injuring his tailbone and preventing him from continuing.

Rescuers had to extricate him and his friends after one of them called 911. They said he was airlifted by helicopter in an evacuation harness, after the medics assessed him at the site and determined that he was ready for transportation.

An image of a crumpled sheet of paper provided by the rescuers shows the printed Google Map and turn-by-turn directions that the hikers used. The printed instructions have several alerts citing restrictions and urging caution.

There is a lesson in there for other prospective hikers, the team said.

“This is not the first time we’ve gone and done a Google Maps rescue,” Maria Masiar, the search manager of the Lions Bay Search and Rescue, said. “This has happened to almost every search and rescue team in the corridor.”

A Google spokeswoman wrote in an email that their app is designed for streets.

“We encourage hikers to use trail maps and apps designed specifically for hiking,” the spokeswoman wrote.

The July 15 rescue highlighted instances in which hikers are led astray after relying on maps they got online for their nature excursions. A 15-year-old boy slid 200 feet down a Colorado mountain, covered in snow, after relying on Google Maps last month, rescuers there said. Another hiker in 2023 in British Columbia was stranded on a cliff after using the navigation system to climb on a nonexistent trail, local rescuers said.

“We’re so used to using Google Maps in our everyday life that I think when people are starting to get into hiking, they think that probably Google Maps will work for backcountry use as well, and that’s just not the case,” said John Blown, of North Shore Rescue, a team based in British Columbia.

According to Google, more than one billion people rely on its app to navigate unfamiliar cities and find new haunts. But the app does not inform hikers about the elevation changes, trail conditions, the difficulty of a hike or weather conditions, according to Lions Bay Search and Rescue.

Improper planning and a lack of education can lead to struggles on a hiking trail. Inexperienced people seeking recreation in the outdoors can become dehydrated, suffer cramps and experience exhaustion if they don’t plan correctly, Mr. Blown said.

The search and rescue team recommended recreationists instead rely on apps designed to navigate mountainous terrain. Some allow hikers to download maps and access them in the backcountry without internet signal, Mr. Blown said. But even those tools are not foolproof.

“A map is only one part of planning,” Lions Bay Search and Rescue said in a Facebook post. “Even the best hiking app can’t replace good judgment.”