Born in Kotka, Tamminen started playing football in a youth sector of his hometown club Kotkan Työväen Palloilijat (KTP). He made his senior debut with the club’s first team in 2018, when the club played in second-tier Ykkönen.[1]
On 17 December 2020, fellow Veikkausliiga side FC Inter Turku announced the signing of Tamminen on a three-year deal, and immediately thereafter loaned him back to KTP for the 2021 season.[4][5]
In July 2022, Tamminen represented Inter Turku in UEFA Europa Conference League qualifiers.[6] After the season, Tamminen was awarded the Anneli trophy by the club's boardroom, which is traditionally granted to the most loyal team player of the club.[7]
On 9 January 2024, Tamminen extended his contract with Inter Turku for the 2024 season.[8] After the season, he was awarded for the most assists of the season, by the Football Association of Finland.
Östers IF
On 18 December 2024, Tamminen signed with Allsvenskan club Östers IF, starting in January 2025.[9]