During and after his time at the University of Oxford, Kilian Günthner sang with two Oxford vocal ensembles. From 2022 to 2025 he was a Tenor 2 in The Oxford Commas, Oxford's lower-voice a cappella group, and from 2023 to 2024 he sang with the Wadham College Chapel Choir, performing the sacred repertoire of regular chapel services and evensong. In the summer of 2024, he organized a joint tour of the Rhineland for both ensembles together with Quinton Lee, with concerts in Düsseldorf, Cologne, and Bad Münstereifel, where he also served as host during the concerts. The following summer, The Oxford Commas, finalists in the UK Open A cappella Competition, brought their show Aca-Demic Weapons to the Edinburgh Festival Fringe, the world's largest arts festival. LondonTheatre1 awarded the production five stars, calling it the strongest of the Oxford a cappella shows it saw at the 2025 festival, while FringeReview praised the group's charisma onstage.