In recent years, reports of submarines in Finnish territorial waters have become more frequent which are leading to public curiosity and concern which is particular since Finland does not operate any submarines of its own.
Published: 30/05/25 | 8:21
The Finnish Navy has acknowledged the rise in these reports. Since the country’s naval forces lack submarines, any such vessel seen in Finnish waters must belong to a foreign nation.
One recent example involved a civilian capturing an image of a submarine in the Archipelago Sea. The sighting quickly fueled online discussions about the sub’s origin. The Finnish Navy later confirmed it was a Swedish submarine which was participating in the “Narrow Waters 25” naval drill.
Annele Apajakari who is the Finnish Navy Chief Public Affairs Officer stated that while it’s not uncommon for submarines to appear in Finland’s territorial waters the details about their presence and movements remain classified.
According to the Navy, foreign submarines must seek authorization from the Finnish Defence Forces to operate within Finland’s waters unless their presence complies with international agreements that also apply to Finland, such as innocent passage en route to another location.
Apajakari explained that several countries active in the Baltic Sea which include Sweden, Germany, Poland and Russia have submarines in operation. However, she also pointed out that a greater number of reports does not necessarily reflect increased submarine activity.
“With more people out and about and nearly everyone carrying a smartphone, sightings are more likely,” she said. She added that many of these turn out to be misidentifications.
For instance, the small islands of Halliluoto and Lokkiluoto near Helsinki are often mistaken for submarines because of visible military structures on them.
If you see a submarine in Finnish waters, the official guidance is to treat it like any other vessel on the water.
“Submarines are required to follow the same maritime rules as other boats, including yielding the right of way, obeying speed limits and adhering to navigation regulations,” said Aleksi Uttula from Traficom which is the Finnish Transport and Communications Agency.
Additionally, if a submarine surfaces, it must display its national flag.
