[2] Erasmus first played at senior level for Namibia in February 2011, aged 15, against a touring Marylebone Cricket Club (MCC) side.
[3] He made his international and first-class debut against Ireland in September 2011 in the 2011–2013 ICC Intercontinental Cup,[4] and at the age of 16, became the youngest player in the team's history.
[13] In May 2019, he was named as the captain of Namibia's squad for the Regional Finals of the 2018–19 ICC T20 World Cup Africa Qualifier tournament in Uganda.
[17][18] In September 2019, he was named as the captain of Namibia's squad for the 2019 ICC T20 World Cup Qualifier tournament in the United Arab Emirates.
[25] In March 2022, in the second match of the 2022 United Arab Emirates Tri-Nation Series, Erasmus scored his first century in ODI cricket, with 121 not out.