Kasey Bos joins Mainz 05

1. FSV Mainz 05 have signed left-back Kasey Bos from A-League side Melbourne Victory FC. The 21-year-old has both Australian and Dutch citizenship  and has signed a four-year deal with the 05ers until 2029. Both clubs have agreed to keep the details of the contract undisclosed.  

Bos was a key player for Melbourne Victory as they finished runners-up in Australia’s A-League last season, featuring in a total of 26 matches (4 goals, 2 assists). He also started in the league’s Grand Final, which ended in a 1-0 defeat against Melbourne City. 

Bos received his maiden call-up to Australia’s senior men’s national team during the most recent international break. The side secured their spot at the 2026 World Cup last Tuesday. Bos’ older brother Jordan also plays for Australia and has been playing in Europe for KVC Westerlo in Belgium for two seasons now. 

“Kasey Bos is a hard-running player on the left flank with strengths in both attack and defence. Additionally, his brave style of play was a strong fit for what we were looking for. He has already been able to prove his talents in the A-League. We believe that he has what it takes to make it in the Bundesliga and that he will be able to develop well when playing alongside a veteran player like Phillipp Mwene,” said FSV sporting director Niko Bungert. 

“The meetings with the club’s sporting management were fantastic and I was also left with a really good impression of the city. The Bundesliga is an exciting league and the level is high. Mitchell Langerak, one of my teammates in Melbourne, was able to give me several tips already. I’m now looking forward to getting to know the team and the fans, in addition to exploring more of Mainz,” said Bos.