This study attends to Generation Zers’ volunteer tourism. It draws on self-determination and goal-setting theories to synthesize a model delineating how the interplay of internal and external environmental motivational factors reshapes green volunteering involvement amid the pandemic, leading to environmental goal attainment and persistent endeavors. The inquiry adopted an online survey-based design with data collected from 340 rising environmentalists. Results first suggest that environmental self-efficacy and social climate are positively related to green volunteering involvement, with environmental self-efficacy exhibiting a more profound effect. These relationships are also moderated by eudaimonic environmental pursuits in that the relationships remain stronger when volunteers pursue eudaimonia to a high degree. Furthermore, involvement is evident in fostering environmental goal attainment, leading to pro-environmental behaviors and advocacy. With the above findings taken together, this investigation sheds light on environmental goal attainment through volunteer tourism amid the COVID-19 turbulence. It brings to light a motivation–goal attainment–behavior model that deserves investigating.