[3] Born and raised in Turku, Tamminen played youth football with several local clubs.

In 2015, she started her senior career with NiceFutis in the Naisten Liiga, the domestic top tier.

The same year, the club also won the Finnish Women's Cup, through a 2–1 win over Tikkurilan Palloseura in the final.

[12] On 5 July the same year, Tamminen signed a new three-year contract with the club, running until the summer of 2026.

[14] Throughout the season, Tamminen set a new league record when the side did not concede a goal for 757 straight minutes, eventually ending the campaign with 13 clean sheets.