Compared to private car ownership, carsharing has emerged as one of the innovative ways of promoting sustainable and more environmentally friendly transportation. As a service thathas existed for decades, carsharing has evolved significantly, with the introduction of several business and service models to create value for users. Despite the popularity of carsharing, private car ownership continues to grow, even though these cars end up being parked most of the time, contributing to congestion in urban areas. Using an exploratory research approach with the aid of speculative design, this thesis investigated the key qualities of a potential digital carsharing service for private vehicle owners, who could share their vehicles with fleet operators during times when the vehicles are idle. Qualitative, semi-structured interviews of ten private vehicle owners wereconducted to investigate the qualities of the potential digital carsharing service. The potential key qualities were grouped under technical and functional qualities according to Grönroos’ Nordic service quality model. The results indicate the importance of designing services that leverage technical qualities such as reward, accessibility, appearance and safety, and security, and functional qualities such as assurance, flexibility, responsiveness, and personalized.