<p>The ongoing U.S.-China technological decoupling presents significant challenges for firms embedded in global innovation ecosystems, prompting a reevaluation of interdependencies within these systems. This study explores how firms adapt their architectural and component innovations in response to shifts in innovation ecosystem connectivity, with a specific focus on how technological decoupling moderates these relationships. Using a longitudinal dataset (2013–2020) from the global high-speed rail industry and employing a triple-difference design, we find that a higher degree of innovation ecosystem connectivity positively influences architectural innovation while exhibiting a U-shaped relationship with component innovation. Importantly, technological decoupling weakens the positive impact of connectivity on architectural innovation and intensifies the U-shaped relationship for component innovation. These findings contribute to innovation ecosystem theory by elucidating how external shocks, such as technological decoupling, reconfigure innovation ecosystem connectivity and reshape innovation dynamics. The study offers practical insights for firms and policymakers, highlighting the need for adaptive ecosystem strategies to maintain innovation performance in fragmented and increasingly isolated global environments.</p>