Rantala made her senior club debut with Team Kuortane in the 2017–18 season of the Finnish Naisten Liiga (NSML). Her rookie season was capped by Team Kuortane winning Finnish Championship (SM) bronze in the 2018 playoffs, the first SM medal in team history.[2]
After four seasons with Team Kuortane, she joined Kiekko-Espoo for the 2021–22 season and won the Aurora Borealis Cup in that season's playoffs. The 2021–22 season marked the first instance of her career in which she averaged more than a point per game (25 points/21 games=1.19) across the regular season and was highlighted by her selection to the Naisten Liiga All-Star First Team.[3]
Ahead of the 2022–23 season, Rantala left Kiekko-Espoo to sign with KalPa.[4] She led all Naisten Liiga defensemen in assists during the 2022–23 regular season, with 32, and was KalPa's top point-scoring defender, notching 39 points in 30 games. In eight games of the 2023 Aurora Borealis Cup playoffs, she contributed two goals and eight assists to KalPa’s SM bronze medal-winning effort. Her play earned a second selection to the All-Star First Team.[5]
Rantala was the league's top scoring defenseman in the 2023–24 season, tallying 34 points (13+21) in 30 games, and was selected to the Naisten Liiga All-Star First Team for the third consecutive time.[6]
SDHL
In early April 2024, Frölunda HC announced the signings of Rantala and KalPa teammate Elisa Holopainen for the 2024–25 SDHL season.[7]
After a knee injury sustained in a preseason game kept her in rehabilitation and off the ice for the entire 2020–21 season,[12] the 2022 Winter Olympics served as Rantala's senior-level IIHF debut.[13][14] She played in all seven games and scored two points in the tournament, a goal and an assist, both tallied against the Russian Olympic Committee (ROC) during the group stage.[15] Her eight penalty minutes led all Finnish players in the tournament.[16]