[6] On 21 September 2020, FC Basel announced that they had hired Rahmen as second assistant trainer under their new manager Ciriaco Sforza.
[7] On 6 April 2021, the club announced that, due to the lack of sporting success, FC Basel 1893 were separating themselves from head coach Ciriaco Sforza with immediate effect.
Until the end of the season, the first team would be looked after by the other previous assistant Rahmen, on an interim, basis as head coach.
[9] On 20 May 2021, FC Basel announced that Rahmen had signed a new contract that made him head coach of the FCB first team.
[11] However, just a few weeks later, on 21 February the club announced that the contract with Rahmen had been terminated, due to "unsatisfactory sportive development of the team and lack of clear perspective".
With Winterthur he managed to qualify for the Championship Group during the regular season, despite coaching one of the weaker teams of the league on paper.
On 14 May 2024, he was announced as the new head coach of Swiss serial champions BSC Young Boys for the upcoming season.
[14] Following a poor start in the league, which saw the team in last place with just six points and one win after nine games played, his appointment with Young Boys was terminated.
However, at the time of his dismissal, Young Boys sat bottom of the Champions League table, following 0–3 and 0–5 losses to Aston Villa and FC Barcelona, respectively.