For eighty years now, the nine-volume series of Moomin books (1945–70) by the Swedish-speaking Finnish writer and illustrator Tove Jansson has been widely recognized as a popular double-address read. The series discusses a wide range of themes, a complexity that makes it both timeless and topical, and has invited multiple studies from a variety of perspectives. This proliferation of research notwithstanding, the Moomin books are still open to interesting interpretations, including ecocritical readings prompted by the ongoing heated debate on climate change and responsibility for our planet. Although some studies have challenged anthropocentric readings of Moominvalley (Jaques 2014; Heinämaa 2018; Czajkowski 2020; Meereboer 2022; Moen Johnson 2023), there has not been much scholarship on its educational applications for green activism yet. My chapter contributes to this field by underscoring the potential of interspecies symbiosis among the inhabitants of Moominvalley for ecological education. Working with insights from the Polish philosopher Andrzej Marzec (2021), I consider how the Moomin characters embody key qualities relevant to current ecological discussion and how the books can and have inspired environmental activism with a tangible impact.