The convicted journalists used classified documents in their work on an article about the Signal Intelligence Center.
The documents contained, among other things, secret information about the center's operations, duties, organization, capacity and acquisitions, writes Svenska Yle.
In December 2017, the report was published in the newspaper Helsingin Sanomat.
According to the prosecutor, the published text contained information that should have been kept secret to protect Finland's external security.
Thinking of appealing
Helsingin Sanomat's current acting responsible publisher and editor-in-chief Antero Mukka tells SVT that they did not publish classified material in the article.
He takes the sentence seriously and is considering appealing it.
At the same time, he is relieved that the district court did not follow the prosecutor's line.
The prosecutor has claimed that all the defendants knew that the article contained information that was classified for national security reasons.
She requested a 1.5-year suspended sentence for the three defendants.
- The process itself has damaged press freedom in Finland.
Threats of imprisoning journalists are enough to create a deterrent effect on reporting on national security and military affairs, says Antero Mukka.
The two journalists' bosses were acquitted, while they themselves are now being sentenced for revealing state secrets.
The journalists deny any wrongdoing.