The aim of this study was to establish 'proof of concept' for a novel approach to HIV and STI testing at a sex on premises venue (SOPV) for gay and bisexual and other men who have sex with men (GBMSM) during late night group sex theme parties. A mixed-methods approach was used, and the study aimed to: (1) Build upon existing SOPV funded service delivery and establish 'proof of concept' for this unique setting within an SOPV; (2) evaluate the uptake and feasibility/acceptability of routine HIV/STI testing for GBMSM during theme parties in SOPV; and (3) identify beliefs/perceptions regarding this health promotion activity and venue suitability. The characteristics of patrons utilising PoCT (Point of Care Testing) were established to help further reach potentially stigmatised, highly sexually adventurous GBMSM. The findings support further PoCT endeavours within MSM communities to target harder to reach communities to reduce the rate of new transmissions of HIV. Findings can inform future health promotion, screening and interventions, as well as to identify a successful method to engage harder to reach GBMSM that need further focused targeting for HIV and STI testing to reduce transmission.