The digital transformation of tourism has reshaped the industry's spatial and temporal dimensions, while smart tourism emerged as a new key concept. This chapter critically examines the evolution from early Global Distribution Systems to the current era of ubiquitous interactivity in tourism, emphasizing how digital tools extend the travel cycle beyond the physical journey. It explores the role of Big Data in tourism planning and management, addressing the challenges of power imbalances in co-creation processes and the commodification of user-generated data. The discussion highlights how automation, artificial intelligence and geo-referenced data influence mobility patterns, service provision and destination management. While digitalization enhances personalization and efficiency, it also raises concerns about data ownership, sustainability and equitable governance. The chapter underscores the need for regulatory frameworks and collaborative governance to balance technological advancements with sustainable tourism development, ensuring that digital transformation benefits both businesses and local communities.