Non-compliance at national parks is a major problem around the world. This study focused on visitors’ intentions to venture off-trail at the Blue Mountains National Park, Australia (BMNP). An extension of the theory of planned behaviour (TPB) with the new ecological paradigm of pro-environmental values (NEP) was developed and tested to understand visitors’ off-trail intentions. We surveyed 325 BMNP visitors through convenience sampling. Subjective norm was the strongest predictor followed by attitudes. The role of perceived behavioural control was not significant. The proposed extended TPB model had a marginal relationship between pro-environmental values and intentions using regression analysis. The overall study results suggested that the role of pro-environmental values is more suitable for predicting general environmental worldviews as compared to the TPB being more suitable for predicting specific behavioural intentions.