Purpose – Building on the theory of supportive design, this study aims to investigate the physical and humanistic environmental factors that influence guests’ social interactions within peer-to-peer (P2P) accommodations. Design/methodology/approach – This study has used a qualitative research design, with 31 in-depth interviews of P2P guests. The grounded theory approach was used to guide data analysis. Findings – This study reveals that the distinctive supportive design and humanistic elements facilitate social exchanges, encompassing functional, cultural, emotional and spiritual dimensions. These elements also helped enhance social connectivity, leading to favorable behavioral outcomes. Practical implications – The findings offer valuable insights for P2P hosts, practitioners and society. By optimizing supportive design, guest interactions, social connections and sustainable community development could be fostered. Originality/value – This research addressed the literature gaps on the specific impact of supportive design and humanistic elements on social interactions within P2P accommodations.