Each year in February, NATO allies gather on the west coast of Norway to practice hunting enemy submarines. While principally directed at Russia, this year’s exercise had an additional audience: Donald Trump.

The Norwegian Sea is the gateway to the Arctic – a region of growing strategic importance even before the president renewed his claim for U.S. control of Greenland while questioning the North Atlantic Treaty Organization’s relevance.

European naval chiefs leading this year’s “Arctic Dolphin” exercise were keen to demonstrate how they’re helping to defend the region, for their own security and that of America.

In frigid temperatures, around 1,000 armed forces personnel from Spain, Norway, Poland, the Netherlands, the U.K., and Germany joined a collection of frigates, helicopters, and patrol aircraft to scour the Norwegian Sea in pursuit of two submarines posing as adversaries.

The aim of the exercise is to stop the threat before it enters “the main heart of the Euro-Atlantic area,” explained Commodore Kyrre Haugen, chief of Norway’s naval fleet.

“That is very important for Europe, for the Euro-Atlantic relationship, and for the homeland security of the U.S.,” he said.

What followed was a game of cat and mouse, with the two conventional submarines – from Norway and Germany – weaving between the Norwegian fjords, attempting to vanish undetected beneath the surface.

To catch them, NATO sets off a series of sonars that use sound waves to detect the boats, either connected to the hulls of the warships or lowered into the sea by helicopters. P-8 surveillance planes assist by using their own radars and deploying sonars known as sonobuoys. These allow NATO to determine the submarine’s distance from the vessel and the speed at which it’s traveling.

It’s not easy: the challenge of the Arctic is that icy, fresh water from the North mixes with the warm, salt water from the Gulf Stream, allowing the submarines to hide in different layers of water. Ice presents an additional obstacle, with noise generated by its movement helping to cloak that of the subs, as well as the hazard it poses for ships.

“That’s why it’s a good place to hide if you’re a nuclear submarine,” said Haugen. “Because it’s hard to detect you.”

The Arctic is home to Russia’s Northern Fleet, a quarter of the world’s natural gas supply, and a wealth of biodiversity that’s becoming more accessible due to climate change.

It’s also home to Greenland, the sovereignty of which has sown deep division and distrust in the transatlantic alliance as a result of President Donald J. Trump’s threats to take it. The president has spent recent weeks minimizing Europe’s role in NATO, diminishing its service alongside US troops in Afghanistan, and questioning whether the alliance would help defend America if it was attacked.

Naval chiefs are eager to stress that military exercises are operating as usual, despite Trump’s grandstanding. U.S. forces are preparing to train with troops in Norway, while U.S. aircraft carriers are touring the region alongside British and French vessels: France’s Charles de Gaulle carrier is due in Sweden this week.

They are also responding with increased surveillance of the Arctic region. Even before Trump’s threats, NATO’s Arctic members – reinforced by the accession of Sweden and Finland – have been calling for the alliance to take the region more seriously. Britain and Norway agreed to jointly operate a fleet of warships to hunt Russian submarines, with the U.K. also planning to place military assets in the country to better prepare for future crises. Norway, Denmark, and Sweden – all Arctic nations – are planning to expand their frigate fleets.

But Russia, too, has expanded its military presence.

The Russian Navy commanded an estimated 64 vessels in 2024, 16 of which are strategic nuclear-powered ballistic missile submarines, according to the Nuclear Threat Initiative. That compares in the same year with an estimated 71 U.S. submarines, 14 of them ballistic missile boats. Russia operates one-third more military bases in the Arctic Circle than all NATO members put together, according to the International Institute for Strategic Studies.

NATO General Secretary Mark Rutte has said the alliance needs to take more collective responsibility for the defense of the Arctic. NATO’s outgoing maritime chief, Mike Utley, told Bloomberg last year that though the alliance has superior capabilities to Russia, they don’t currently have the military resilience for a protracted conflict.

“I wouldn’t say we lost those capabilities, but I will say that we have not exercised as we had to, and we have to regain and rebuild those capabilities as soon as possible,” Rear Admiral Joaquín Ruiz Escagedo, Commander of the NATO maritime group taking part in the exercise, told Bloomberg. That’s because anti-submarine warfare wasn’t a priority for NATO allies over several decades, due to the focus on land forces in places like Iraq and Afghanistan, he said.

Sweden’s former foreign minister, Tobias Billström, who negotiated the country’s entry to NATO, said he doesn’t believe the alliance has enough of a grasp on Russia’s submarine fleet operating in the Arctic and may need to develop more capacity in the region to detect and track them.

NATO has launched an enhanced vigilance mission, “Arctic Sentry,” which will mirror how the alliance operates in Eastern Europe and the Baltic, though it mainly involves reorganizing and better coordinating the alliance’s existing assets.

“It’s certainly an improvement, and it shows willingness, which, after all, is what was being asked by Washington,” Billström said.

During the Norwegian Sea exercise, once the submarines are detected, they and the naval fleet practice tactical maneuvers in a war-style scenario that mimics how they would attack each other with torpedoes, without actually firing them.

It’s like “playing hide and seek,” said Lieutenant Commander Marc Jereskes of the Dutch Navy.

This is no game, though: if Russia launches a ballistic missile from one of its submarines in the Arctic, it is capable of hitting the U.S. mainland.

With greater investment and advancing technology, Russia’s submarines are becoming more deadly and harder to track. Nuclear submarines, unlike the conventional ones used on Arctic Dolphin, are faster and don’t need to come to the surface as often. Last year, President Vladimir Putin unveiled Russia’s latest submarine, capable of carrying Poseidon torpedo drones, which he said had evaded interception in tests.

Melting ice is meanwhile opening new shipping routes, which Russia’s shadow fleet is taking advantage of, helping to fuel its war1 against Ukraine. One hundred sanctioned ships sailed through the Northern Sea Route along Russia’s Arctic coast in 2025, 87 more than the previous year, according to the Bellona Environmental Foundation. Though the numbers are still small, container ships are also increasingly using the route, which can halve the 40-day Asia-to-Europe trip via southern Africa.

“As the Arctic becomes more interesting, there’s new possibilities for conflict,” said Captain Jim Robertsen, chief of Norway’s submarine service.

With climate change come warming waters, which raise the prospect of greater competition for fossil fuels, rare-earth metal deposits, and fisheries. About 90 billion barrels of undiscovered oil and 1,670 trillion cubic feet of undiscovered gas may lie inside the Arctic Circle, according to the US Geological Survey. The U.S. Coast Guard said last year it was monitoring a group of Chinese research vessels in the U.S. Arctic. NATO’s maritime strategy states that China is “surging its presence in the High North and the Arctic while remaining opaque about its intentions.”

For now, the issue of Greenland seems to have receded as the attention of Western leaders turns back to the peace negotiations between the U.S., Ukraine, and Russia. Officials, however, are not sure that Arctic Sentry and the agreement to continue discussing the issue will be enough to placate Trump. At the NATO and EU level, there’s a recognition that the Greenland question has not been shelved.

With the region becoming ever more contested, it demonstrates why NATO remains such a valuable alliance, even for non-Arctic nations, according to the Spanish Navy’s Ruiz Escagedo.

“The U.S., Europe, (and) Canada have all benefited from this alliance in the past,” said the rear admiral. “Let’s keep what we have.”