Finland had needed overtime to knock out the United States in the Quarter-finals, while Sweden had progressed more comfortably against Latvia. That extra rest looked to be paying dividends just 36 seconds in when Linus Eriksson diverted Anton Frondell's speculative effort past the goaltender.
But Finland soon found their rhythm and had more shots than their neighbours in the opening period and, more importantly, made one of them count in the 17th minute, when Atte Joki set himself and fired home after a sustained period of pressure.
Yet it was Sweden again who came out firing at the start of the second period, as a smooth attack resulted in Ivar Stenberg powering the puck through a crowd and into the top corner.
But once again the Swedish lead did not last; this time it took less than a minute for the Leijonat to equalise when Jasper Kuhta was in the right place to force home a scrappy rebound effort.
Sweden took the lead for the third time in the 15th minute of the second when Eddie Genborg's strike from behind the net deflected in off Petteri Rimpinen, only for Finland to level for a third time in the 15th minute of the third, as the puck dropped kindly for Joona Saarelainen to finish.
Blagult edged the shooting stats in overtime, in which they survived a late powerplay following a slashing call against Viggo Bjorck, but neither side could find the winning goal.
In the shootout, first blood went to Finland when Matias Vanhanen scored their second penalty, and that looked to be enough as Sweden missed their first four, only for captain Jack Berglund to keep them alive with their fifth penalty.
Julius Miettinen missed Finland's fifth, sending the shootout to sudden death. Following three more Finnish misses, Frondell really attacked the Finnish goal and beat Rimpinen for pace to win the shootout 2-1 for Sweden after eight penalties each, and send them to the Final, 4-3.
Finland must console themsleves with the chance to win bronze when they meet Canada tonight, before Sweden go for gold against Czech Republic at 02:30 Swedish time.
Follow the medal matches of the 2026 World Junior Hockey Championship on Flashscore.