RFC Liège Matthys started playing football at Euro Youth Liège 75, which merged with Daring Club De Cointe in 2007. RFC Liège ended up narrowly missing out on promotion to
First Amateur Division.
Eupen On 17 July 2019, Matthys secured a transfer to top division
Belgian Pro League club
Eupen, where he signed a three-year contract, becoming the backup to
Ortwin De Wolf alongside
Abdul Manaf Nurudeen. In his debut season with Eupen, he made only one official appearance: a cup match against
Cappellen, which Eupen won after a penalty shootout.
RWDM (loan) In August 2020, Eupen sent Matthys on loan to
RWDM for one season. He made his competitive debut for the club on 10 October 2020 in the cup match against
Union Rochefortoise, which RWDM won 8–1. When starting goalkeeper
Anthony Sadin was deemed unfit for the league match against
Lommel on 24 January 2021, Matthys made his debut in
Belgian First Division B. RWDM lost this match 3–2, despite having a 2–0 lead at half-time. A week later, he also started the derby against
Union Saint-Gilloise, which RWDM lost 2–0. Afterwards, Sadin took over the starting job once again.
MVV In July 2021, alongside Eupen teammates
Simon Libert and
Marciano Aziz, Matthys was sent on a one-season loan to Dutch
Eerste Divisie club
MVV, where Matthys became the backup to
Thijmen Nijhuis, who had been loaned from
Utrecht in the same transfer window. On 26 October 2021, Matthys made his competitive debut for MVV in the cup match against
ACV Assen, which head coach
Klaas Wels had him start. In this match, Matthys not only kept a clean sheet, but also delivered an assist to
Mart Remans' 2–0 goal. On 5 November 2021, he made his league debut for MVV in the 1–0 win over
Jong AZ, keeping another clean sheet in another 90-minute performance. Matthys stayed on as starting goalkeeper from then on, and was named in the Eerste Divisie Team of the Year for the
2021–22 season. Following another impressive
season, Matthys had the most saves in the league (166) as well as the best save percentage (72%) and helped the club secure a spot in the promotion play-offs. As a result of his outstanding performance, he was honoured with a consecutive selection to the Eerste Divisie Team of the Year.
Castellón On 18 June 2025, Matthys signed a two-year contract with
Segunda División side
Castellón. ==Career statistics==