This research supports the evolution of border studies by advancing recently elaborated theoretical insights convincingly captured as borders in motion and the multiscalar nature of borders. Drawing on ongoing empirical research in Yunnan province, China, the combined perspectives tender a new approach of 'relational motion' to inform analyses interrogating the complex and dynamic nature of border-related phenomena occurring in, across and beyond Yunnan. We propose a new consideration of the ways border phenomena manifest, and detail outcomes by highlighting a range of interrelated processes. Our focus on processes, as opposed to borders or borderlands only, provides a critical insight to understand how border-related phenomena shape - and are shaped by - a diverse range of initiatives whose nature are connective and discrete, distinct and obscure, theoretical and empirical. Theoretical discussion is centred on four empirical sections: Kunming as a border and borderlands metropolis; Yunnan as an integrative energy centre; Yunnan as a focal point for transregional security; and transborder migration in Yunnan. Empirical insights contextualize how macroscale initiatives, such as the Belt and Road Initiative (BRI)- manifest at multiple scales through border-related phenomena. The research presents fresh empirical and theoretical insights into China's south-west to understand this dynamic, nuanced region better.