Asteroids and comets are “living fossils” that were initially the sources of planet formation. They are considered to have experienced minimal alterations since the early Solar System. Observations have revealed the presence of water (including hydrated minerals) and organics on carbonaceous asteroids and comets, suggesting the delivery systems of these materials to Earth that can connect with the development of the habitable environment. This finding has enhanced global efforts in space missions to visit and explore these small bodies, as well as returning samples from them. We are now harvesting the first fruits from these long-term efforts. The present session highlights the scientific findings from JAXA’s Hayabusa2 targeting carbonaceous asteroid Ryugu and compares them with those from NASA’s OSIRIS-REx exploring carbonaceous asteroid Bennu. Together, this session introduces international efforts in future small body exploration missions that uncover the conditions necessary for building habitable planets around a star.