Thomas Beelen

Beelen started playing football for VV Hierden. He joined FC Twente's academy at the age of 10. However, he left the club while FC Twente was in financial trouble. He signed for VVOG the following year.

PEC Zwolle

Beelen joined the academy of PEC Zwolle in 2017. He made his professional debut for PEC Zwolle in the Eredivisie on 23 April 2022 in a 2–0 win away against RKC Waalwijk as a substitute for Gervane Kastaneer. A week later, he made his home league debut in the Eredivisie starting in a 2–1 defeat against PSV Eindhoven at the MAC³PARK Stadion. In June 2022, Beelen signed his first professional contract to mid-2023 with an option for another year with PEC Zwolle despite their relegation to the Eerste Divisie. Beelen scored his first professional goal in a 13–0 win against Den Bosch on 3 March 2023, which was the biggest-ever win in the Eerste Divisie. Beelen was a regular starter for a PEC Zwolle side that was immediately promoted back to the Eredivisie in the 2022–23 season. He attracted interest from Eredivisie clubs PSV Eindhoven, Feyenoord, AZ Alkmaar and FC Twente.

Feyenoord

On 8 July 2023, PEC Zwolle and Feyenoord announced that the clubs had agreed Beelen's transfer to Feyenoord and the full details would be announced when the transfer was fully finalized. Two days later, the transfer was finalized. Beelen made his Feyenoord debut on 13 August 2023, in a goalless draw against Fortuna Sittard. On 13 December 2023, he was praised by his manager…

As of match played 3 May 2025

Feyenoord

KNVB Cup: 2023–24 Johan Cruyff Shield: 2024