Prosecutors sought prison terms of more than two years, warning the incident could have sparked blackouts and power price spikes.
The incident fueled calls to crack down on Russia’s “shadow fleet” and prompted NATO to step up seabed patrols following a string of cable disruptions in the region.
The trial was also seen as a test case for holding actors accountable for attacks on critical seabed infrastructure. But it collapsed over maritime law provisions and doubts about intent.
The court sided with the defense, ruling the damage occurred outside Finnish jurisdiction and ordering the state to reimburse the legal fees of the defendants.
Judges acknowledged the cable breaks caused economic damage to Finnish firms, but said the risk of widespread blackouts was unlikely as it required “other serious disturbances” alongside extreme weather.
The three defendants, who denied any wrongdoing, were barred from leaving Finland for nine months but departed in September after their travel ban was lifted.