[1][2] He made his List A debut on 28 September 2020, for North West Warriors in the 2020 Inter-Provincial Cup.
[3] On 11 January 2021, Olphert was added to Ireland's squad as a net bowler for their matches against the United Arab Emirates and Afghanistan.
[6] He made his Twenty20 debut on 18 September 2021, for North West Warriors in the 2021 Inter-Provincial Trophy.
[8] In June 2022, Olphert was named in Ireland's Twenty20 International (T20I) squad for their two-match series against India.
[10] In May 2023, Olphert was named in Ireland's Test squads for their tour of England in June 2023.