["International Journal of Tourism Research, Volume 28, Issue 3, May/June 2026. ", "\nABSTRACT\nTourism innovation is widely promoted as a cornerstone of sustainability transitions, yet environmental pressures in many destinations continue to intensify. This study questions the implicit assumption that innovation delivers environmental benefits in a monotonic and cumulative manner. Using a balanced panel of 31 Chinese provinces from 2008 to 2024, we construct a Tourism Innovation System Index and a Green Tourism Performance Index and apply a panel threshold model to examine regime‐dependent effects. The results show that innovation's environmental impacts are nonlinear and directionally unstable, shifting across structural regimes defined by institutional thresholds. Innovation amplifies environmental pressure below critical capability levels but supports environmental upgrading once thresholds are crossed. These regime transitions are conditioned by public cultural capacity, tourism openness, and tourism dependence, and are most pronounced in constrained regions. The findings challenge innovation‐centered sustainability narratives and highlight the risks of policy strategies that promote innovation without regard to system readiness.\n"]