In June 2018, he was named in the Netherlands'
Twenty20 International (T20I) squad for the
2018 Netherlands Tri-Nation Series. He made his T20I debut for the Netherlands against
Ireland on 12 June 2018. In July 2018, he was named in the Netherlands'
One Day International (ODI) squad, for their series
against Nepal. He made his ODI debut for the Netherlands against
Nepal on 1 August 2018, taking 3/30 on debut. In December he was named in the squad for the
2018–19 Oman Quadrangular Series, playing in all three of the Netherlands' matches during the tournament. On 1 October 2018 Klaassen signed a two-year contract with English county team
Kent County Cricket Club. He had played for the county Second XI in friendly matches during the previous English season and against Kent in warm up matches ahead of the
2018 t20 Blast competition. He made his
first-class debut on 31 March 2019 for Kent against
Loughborough MCCU, as part of the
Marylebone Cricket Club University fixtures. In Dutch domestic cricket Klaassen has played for VOC Rotterdam, winning the
Topklasse, the Dutch domestic title, with the club in 2018. He was the leading bowler in the competition during the 2018 season, taking 29 wickets at an
average of 14.10 runs per wicket. In the 2018/19 northern hemisphere winter he played in Australia for
Monash Tigers in
Victorian Premier Cricket. Klaassen played in the
2019 ICC T20 World Cup Qualifier tournament in the United Arab Emirates and in September 2021, was named in the Dutch squad for the
2021 ICC Men's T20 World Cup. In April 2022, he was bought by the
Manchester Originals for the
2022 season of
The Hundred. Having not made an appearance for the club in 2024 due to a back injury sustained on international duty, Klaassen signed a new one-year white-ball contract with Kent in December 2024. He agreed a further deal with the club in January 2026, tying him into them until the end of the 2027 season. ==References==