ALONG UKRAINE’S EASTERN FRONT — They are fishing nets, but they are not catching fish. They are catching Russian drones.

The nets are strung over roads leading to hot spots in Ukraine’s eastern front, above military checkpoints and artillery positions. They are sewn in cities far from the front, or shipped from Nordic ports, donated by fishermen who no longer need them.

Their purpose is to thwart the Russian drones that now swarm the skies above the front lines and swoop in on practically anything that moves, whether it is an armored vehicle racing to resupply troops or a soldier hiding in a tree line.

With their dense mesh, the nets can tangle drone propellers and immobilize the weapons. They are a simple but effective countermeasure against drones that are often too fast to shoot down and can fly deep behind the front to strike logistical routes once out of reach.

Russia has also increasingly used drones connected by fiber-optic cables rather than ones that rely on electronic signals. The cables make them immune to jamming, a standard method used to counter drones on the battlefield. The nets have become one of the few remaining ways to catch drones before they hit.

“Military engineers noticed that even an ordinary fishing net could stop or damage an enemy drone,” Lt. Col. Maksym Kravchuk, head of communications for the Ukrainian army’s engineering forces, recently told Ukrainian news media. He added that nets were now being installed “along the entire front line, from east to south.”

Moscow was the first to use nets in this way in this war, said Federico Borsari, an expert on technology warfare at the Center for European Policy Analysis, though on a limited scale in mid-2023. At that time, Russian troops used the nets to counter small attack quadcopters that Ukraine deployed to strike soldiers and vehicles.

Last year, the Russian state news agency Tass reported that Moscow’s forces had begun installing fishing nets over roads in parts of occupied northeastern Ukraine. Footage verified by The New York Times also shows nets strung outside Bakhmut, a city Russian forces captured in 2023 after a bloody battle.

As Moscow surged ahead in the drone development race recently, the Ukrainian army adopted a similar tactic.

Now Kyiv has plans to cover key roads along the entire front line with nets, creating what soldiers call “net corridors” that offer vehicles a safer passage.

The project is slowly reshaping Ukraine’s front-line landscape. Roads once lined with trenches and barbed wire are now also draped in mesh suspended from cables strung between poles. Driving through them feels like entering a translucent tunnel.

Military vehicles have also been retrofitted with nets, and some even sport chain-link cages that recall “Mad Max.” The cages cause the drones to explode a few feet from the vehicle, minimizing the impact.

The use of the nets reflects a defining feature of this war, where antiquated yet effective defensive means often counter cutting-edge weapons.

To shoot down drones, some Ukrainian units still rely on World War II-era machine guns. Recently, a City Council official from Kherson, a front-line city pounded by Russian drones, urged residents to carry scissors to cut fiber-optic cables that may be connected to drones.

“The Russian invasion of Ukraine, from a military standpoint, is a clear example of a mix of the old and the new,” said Borsari, the technology warfare expert.

In recent months, local Ukrainian authorities have begun building net corridors in Sumy, a region in the northeast that Russian forces have partly invaded, and in the Donetsk region in the east, the main theater of the war.

It remains unclear how many miles of nets have been installed.

As Moscow has been flying drones deeper into Ukraine, it has hit the main access road leading into the embattled eastern city of Kostiantynivka, which is otherwise surrounded from the east, south and west.

To protect this vital lifeline, Ukrainian forces have begun installing a large net corridor over a stretch of that road. On a recent morning, service members were digging holes for poles along the roadside and unfolding large rolls of thin netting, which they then lifted onto the poles.

With potentially hundreds of miles of roads to cover, Kyiv is now turning to charities to secure more nets.

Ludvig Ramestam, a founder of the Swedish nonprofit group OperationChange, said the organization had provided 250 metric tons of nets so far this year.

They source them from partners in Nordic countries with large fishing industries, like Denmark.

“We give these nets a second life,” Ramestam said, joking that his organization was going to “empty the harbors.”