Since curbing the upward trend of energy consumption has become a global pursuit in achieving environmental sustainability, macroeconomic factors such as energy transition and international tourism may be of crucial importance in mitigating environmental degradation. However, the combined role of economic welfare, population, international tourism, and energy transition towards mitigating environmental degradation has not been investigated extensively. In this regard, this study looks at the combined interplay between these variables for a panel of ten southeastern Europe (SEE) countries, covering the period of 1997–2018 under the umbrella of the environmental Kuznets curve (EKC) phenomenon. Two indicators of environmental degradation, namely, ecological footprint and carbon intensity, were used in this study. The ordinary least squares (OLS) regression with Driscoll–Kraay (DK) and the panel Method of Moments Quantile Regression (MMQR) with fixed effects were used to disclose the following outcomes: firstly, the environmental degradation–economic welfare nexus firmly established an inverted U-shaped relationship, thereby depicting the validity of the EKC hypothesis. Secondly, energy transition and international tourism manifest negative effects: they induce environmental degradation. Thirdly, the impact of the population is positive but not significant. Given the empirical outcomes, energy transition and international tourism are proposed as critical to mitigating the environmental degradation of the inspected sample of countries.