Nature exposure has been renowned for its positive physiological and psychological benefits. Recent years have seen a rise in nature immersion programs that make use of Guided Forest Therapy walks in a standard sequence of sensory awareness activities to expose participants to natural environments in a safe but effective manner. The study aimed to compare the efficacy of guided versus unguided nature immersion, upon three dependent variables of mood, nature connectedness and heartrate. 51 participants were assigned to either guided or unguided nature immersion. Nature connectedness (Connectedness to Nature Scale, CNS), Environmental Identity Scale, EID short form) and mood (Positive and Negative Affect Scale, PANAS) were assessed before and after nature immersion, while heart rate was tracked continuously by a wristwatch heart rate tracker throughout the 2-h experience. Demographics and general health practice (GHP) information were also collected. A mixed model ANOVA revealed that nature connectedness and mood (but not heart rate) improved post-immersion for all participants. Comparing the guided/unguided conditions, there were no significant differences in the change in nature connectedness, mood or heart rate. Comparing within the five segments within the standard sequence in the guided condition, the third and fifth segments revealed a significantly lower heart rate compared to the baseline heart rate.