[2] Cashmore attended Tauranga Boys' College, where he played rugby for their first XV team.
[4][5] Cashmore has represented Bay of Plenty in the National Provincial Championship since 2021; he was named in their full squad for the first time for the 2022 Bunnings NPC.
[6] On 9 November 2023, Cashmore was named in the Blues squad for the 2024 Super Rugby Pacific season.
[7] Cashmore was named in the Hurricanes squad for the 2025 Super Rugby Pacific season on 12 November 2024.
[8] In 2022, Cashmore was named in the New Zealand Under 20 team[9] and played in all three matches of the 2022 Oceania Rugby Under 20 Championship.