Jonas Olsson of Breaking Defense reports that NATO’s Baltic anti-submarine warfare exercise Merlin began this week, the first since Sweden joined the alliance in 2024, prompting commanders to describe the Baltic Sea as a “lake full of NATO submarines.” The drill unites submarines, warships, aircraft, and helicopters from several NATO nations to enhance undersea defense in the shallow, strategically tense region, where Russia operates a small fleet of Kilo-class submarines. Sweden’s accession has transformed its naval role from national defense to protecting NATO’s eastern flank, but its modernization efforts face challenges: delays and soaring costs have pushed the delivery of new A26 Blekinge-class submarines and larger Luleå-class frigates into the 2030s. Despite these setbacks, NATO leaders say Sweden’s advanced stealth submarine capabilities and closer coordination significantly boost the alliance’s deterrence and maritime strength in the Baltic. They write:
As a NATO anti-submarine warfare exercise kicked off this week, top commanders said that with Sweden in the alliance, the Baltic Sea is now a “lake full of NATO submarines” under unified command.
“With Sweden’s addition … that was our first opportunity to add another submarine nation to NATO. And now we have, basically, a Baltic lake full of NATO submarines,” NATO’s top submarine commander, US Rear Admiral Bret Grabbe, said at a press briefing at the Dutch frigate HNLMS Van Amstel docked in Stockholm.
The exercise, NATO’s dedicated Baltic anti-submarine warfare drill called Merlin, brings together subs from Sweden and Germany, surface ships and helicopters from France, Germany, the Netherlands and Sweden, and a maritime patrol aircraft from the United States to practice all-domain ASW in the shallow, mine-prone, relatively shallow Baltic environment. […]
ight now there’s a three- or four-to-one ratio of NATO ships to adversary ships around the Area of Responsibility (AOR), and “that’s quite an impressive deterrent feature that we have when we’re working together,” Grabbe said. […]
Sweden’s current fleet includes three upgraded Gotland-class and one Södermanland-class submarines, plus five Visby-class stealth corvettes — all optimized for Baltic ASW with quiet propulsion and advanced sonars.
Next-generation A26 Blekinge-class submarines (HMS Blekinge and HMS Skåne) are under construction by Saab Kockums. […]
However, there are also delays with the new surface combatants: four new larger frigates to replace older ships and complement the Visby-class vessels, which are under mid-life upgrades into the 2040s, adding air defense like Sea Ceptor. […]
When pressed on priorities, such as timeline, capacity, or economy, the Sweden’s naval chief emphasized a balanced approach: “I would say, all three of them, economy as well,” Norlén said. The announcement is expected “in a short time,” though no specific date was provided.
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