The line stretched from the southernmost Vaalimaa border post to the city of Kotka. On Saturday morning, the queue was 60 kilometres long, but fell to half that by evening.
The backlogs at the Imatra and Nuijamaa crossing points further north have only been about 2-4 kilometres long.
Police have opened a temporary parking lot and lowered speed limits in the area to 80 kilometres an hour.
Border officials blame this weekend's long lines on various reasons, from the end-of-June rush to a backlog of goods that were not delivered during the Midsummer holiday weekend.