The submarine hunts or submarine incidents were a series of several incidents involving foreign submarines that occurred in Swedish territorial waters during the Cold War, attributed in Swedish media to the Soviet.
On October 27, 1981, the Soviet submarine U 137 became stranded deep inside Swedish waters. The Swedish Navy responded aggressively to these perceived threats, increasing patrols in Swedish waters, mining and electronically monitoring passages, and repeatedly chasing and attacking suspected submarines with depth charge bombs, but no hits or casualties were ever recorded. This incident increased scrutiny of future submarine incidents.
Reports of new submarine sightings and television imagery of Swedish Navy helicopters firing depth charges into coastal waters against suspected intruders became commonplace in the mid-to-late 1980s. They remain, for many Swedes, one of the iconic images of the Cold War and of the Swedish relation to the Soviet Union—for some underlining what was considered a major threat to Swedish sovereignty, while for others illustrating the tense atmosphere of the time. However, the reports of these incidents are not uncontested, and an intensive debate emerged early on. This debate unfolded somewhat, but far from exclusively, along leftwing/rightwing lines, and became tied up with the larger issues of relations to Moscow and Swedish armed neutrality. The Soviet Union consistently denied that it was responsible for violating Swedish waters, and claimed that the U 137 had only crossed the border because of navigational faults. Russia today maintains this stand. While the submarine sightings subsided with the fall of the Soviet Union, the debate about these events has reemerged sporadically. They have been the subject of a number of government investigations in Sweden, and continue to attract media attention.
Ola Tunander attributes the majority of these incursions to be of NATO origin:
Following the stranding of a Soviet Whiskey-class submarine in 1981 on the Swedish archipelago, a series of massive submarine intrusions took place within Swedish waters. However, the evidence for these appears to have been manipulated or simply invented. Classified documents and interviews point to covert Western, rather than Soviet activity. This is backed up by former US Secretary of Defense Caspar Weinberger, who stated that Western "testing" operations were carried out regularly in Swedish waters with Swedish cooperation. Royal Navy submarine captains have also admitted to top-secret operations.