ABSTRACT Just as early navigators set sail to explore the oceans, astronauts venture into space to explore distant planets, moons, and celestial bodies. Exploring the depths of the oceans or travelling into the cosmos represents a quest for discovery, pushing the boundaries of human knowledge and understanding. Whether delving into the depths of the sea or reaching for the stars, the allure of these uncharted territories beckons adventurers and scientists alike to uncover their secrets and unlock new possibilities for exploration and discovery. This hybrid-water-space existence is giving rise to novel forms of heritage, both tangible and intangible. Consequently, discussions surrounding the past, present, and future of underwater and space realms are increasingly relevant. This article aims to delve into the multifaceted realms of underwater and space cultural heritage, with a particular focus on their archaeological significance and potential for tourism. By examining these two domains, it hopes to uncover rich narratives of human history, technological innovation, and cultural heritage that span both terrestrial and extraterrestrial landscapes.