In February 2017, Klaasen was named in South Africa's
Test squad for their series
against New Zealand, but did not play. In February 2018, Klaasen was added to South Africa's
One Day International (ODI) squad for their series
against India, replacing an injured
Quinton de Kock. He made his ODI debut against
India on 7 February 2018. He won his first international
man of the match award in his second ODI, in the fourth ODI of the home series
against India, with a match-winning 43 runs off 27 balls. In the same month, Klaasen was named in the South Africa
Twenty20 International (T20I) squad, also for their series against
India. He made his T20I debut for South Africa against India on 18 February 2018. On 21 February, Klaasen scored his maiden T20I fifty in the
second T20I against India which South Africa won by 6 wickets, he was also awarded the man of the match for his 69 runs from 30 balls, which included 3 fours and 7 sixes. In February 2018, Klaasen was named in South Africa's
Test squad for their series
against Australia, but did not play. In August 2019, he was added to South Africa's Test squad for their series
against India, replacing the injured
Rudi Second. He made his Test debut for South Africa, against India, on 19 October 2019. On 29 February 2020, Klaasen scored his first century in an ODI match, making an unbeaten 123
against Australia. In January 2021, Klaasen was named to
captain the South Africa T20I squad for their away series
against Pakistan. In April 2021, Klaasen was again named as South Africa's T20I captain, this time for their home series
against Pakistan, after
Temba Bavuma was ruled out due to an injury. In September 2021, Klaasen was named in the South Africa squad for the
2021 ICC Men's T20 World Cup. On 8 January 2024, Klaasen announced his retirement from Test cricket, having played only 4 matches since his debut in 2019. In May 2024, he was named in South Africa’s squad for the
2024 ICC Men's T20 World Cup tournament. In June 2024, he went on to score the fastest fifty in the history of ICC events finals, men and women, surpassing the record of
Alyssa Healy scoring it in 23 balls. South Africa lost the final by 7 runs to India after Klaasen was dismissed by Hardik Pandya in the 17th over for 52 runs off 27 balls. Earlier he smashed 2 fours and 2 sixes in the 15th over bowled by
Axar Patel to bring the equation to 30 runs needed off 30 balls. On 2 June 2025, Klaasen announced his retirement from international cricket. His decision, shared via social media, was influenced by a desire to spend more time with his family and to focus on franchise-based T20 leagues. He featured 122 international games, including 4 Tests (104 runs), 60 ODIs (2,141 runs) and 58 T20Is (1,000 runs). ==References==