The midfielder has signed a three-year contract with the Welsh outfit, sealing a return to the Liberty Stadium on a permanent deal following a successful loan spell with the Swans last season.
Fer made 11 appearances and helped Francesco Guidolin’s side to a 12th-place finish in the 2015/16 Premier League campaign. The 26-year-old enjoyed an indifferent two-year spell at QPR, whereby he scored eight goals in 50 appearances following a switch from fellow English club Norwich City.
Fer began his career at the world-renowned Feyenoord academy, going on to make over 100 appearances for the club after being handed his debut at the tender age of 17.
The midfielder has 11 caps for his national team and was part of the squad for the 2014 World Cup in Brazil, netting against Chile in the group stage.
Fer is expected to compete with the likes of Nathan Dyer and Gylfi Sigurdsson for a position in the starting line-up.