The study of pro-environmental tourist behaviours (PEB) frequently relies on self-reported measures of intentions and/or attitudes. Issues with these approaches are reviewed and compared with quasi-experimental field studies that measure actual behaviour and are higher in external validity. The research note argues for an expansion of these studies’ contexts, the interventions used in experimental conditions and types of PEB measured as outcome variables. By way of example, a small between-subject quasi-experiment is presented, using an innovative virtual reality game developed by the author to encourage tourists’ connection with Australia's Great Barrier Reef.Passengers were presented with the game and a control condition (a VR video) on alternate days. The recorded behaviour was their selection of a thank you gift from the options, including one target PEB (conservation donations). The aim of this research note is prompt greater consideration of how we might measure actual PEBs in (eco)tourism studies.