MILAN — French, Dutch, and other NATO allies spent the week carrying out a game of underwater hide-and-seek in the Baltic Sea, hunting German and Swedish submarines with the help of a U.S. P-8 Poseidon aircraft and other detection systems.
The drill was part of NATO’s Playbook Merlin 2025, a Sweden-led regional military exercise focused on sharpening allied anti-submarine warfare skills.
Participating forces included a German Navy U-35 submarine and a Swedish Södermanland-class submarine, as well as a U.S. maritime patrol aircraft. Surface ships and helicopters from France and the Netherlands also took part, along with other contributions.
“The scenarios focused on honing submarine hunting skills with the German and Swedish ones playing the role as the hunted subs while surface ships, helicopters, and the U.S. P-8 aircraft rehearsed their skills in locating them utilizing sonar and other techniques,” Arlo Abrahamson, spokesperson for NATO’s Allied Maritime Command, told Defense News.
This was the second edition of the exercise, which the spokesperson said had evolved from a small playbook training engagement the previous year to a significant, major exercise for the military alliance.
Operating in the Baltic Sea is markedly different from locating submarines in the Atlantic and Mediterranean Seas, he added, primarily due to the shallower waters found in this environment.
For example, the average depth of the Baltic Sea is only 54 meters, while the mean depth of the Mediterranean Sea is 1,500 meters, according to MarineFinland.
“Both Sweden and Germany are playing a leading role and teaching other non-Baltic allies how to locate and monitor submarine activity in the Baltic Sea,” Abrahamson said.
Last month, over the span of a few days, the Russian submarine Novorossiyskwas spotted surfacing off the coast of France, and the Royal Swedish Navy reported that it had detected and escorted another Russian submarine in the Baltic Sea.
Elisabeth Gosselin-Malo is a Europe correspondent for Defense News. She covers a wide range of topics related to military procurement and international security, and specializes in reporting on the aviation sector. She is based in Milan, Italy.
