Before BALTOPS: Russian navy in Skagerrak and Baltic Sea

Russian naval activity in the run-up to BALTOPS 2025 in the Skagerrak and western Baltic Sea

On 20 May 2025, the Russian frigate "Admiral Kasatonov" (project 22350) left its home port of Severomorsk. Together with the Udaloy class destroyer "Vitse Admiral Kulakov" (project 1155), it was sighted in the Skagerrak on 26 May. While the "Admiral Kasatonov" remained in the sea area, the "Vitse Admiral Kulakov" continued its journey through the Kattegat and the Great Belt to the western Baltic Sea.

Analysts assume that the "Admiral Kasatonov" deliberately remained in the Skagerrak in order to gain an overview of the NATO forces deploying in the run-up to BALTOPS 2025. After completing the first transfer movements of the participants, including the "USS Mount Whitney", it continued its transit to the Baltic Sea on 5 June.

The "Vitse Admiral Kulakov" had previously taken part in exercises in the Baltic Sea and was observed returning to the Skagerrak on 4 June. The ship had previously been documented several times shadowing western units, including the German frigate "Bayern".

The "Admiral Kasatonov" is a modern Admiral Gorshkov class frigate equipped with Kalibr and Oniks cruise missiles, Redut air defence system and modular sensor technology. Commissioned in 1981, "Vitse Admiral Kulakov" is an ageing unit, but thanks to upgrades it remains an integral part of Russian anti-submarine warfare operations.

"Admiral Kasatonov" (Gorshkov class). Photo: Michael Nitz

There was no evidence that the two Northern Fleet units were directly involved in escorting Shadow Fleet tankers. Their deployment therefore served primarily to gather information and send strategic signals.

BALTOPS 2025 and Baltic Sentry

Independently of the BALTOPS 2025 manoeuvre, NATO has been operating Baltic Sentry, a permanent operation to protect critical underwater infrastructure in the Baltic Sea, since January 2025. Both activities took place in parallel in June 2025 without being operationally linked. While BALTOPS is primarily geared towards interoperability and combat capability, Baltic Sentry focuses on maritime surveillance in the area of undersea energy and communication links and serves to increase resilience against hybrid threats in the maritime space. In addition to manned units, unmanned systems are also deployed. The platforms deployed for Baltic Sentry that were not involved in BALTOPS included the Finnish speedboat "Hamina" and the Swedish stealth corvette "HSwMS Visby".