BACKGROUND: Sensory rooms, widely used in psychiatric care, offer customizable environments designed to enhance comfort and reduce distress. Although our previous research demonstrated that sensory room use was associated with increased vagal activity in healthy individuals, its physiological effects in individuals with depression remain unclear. AIM: This study aimed to examine the effects of a sensory room intervention on autonomic function and psychological outcomes in adults with depression. METHODS: Twenty adults with depression participated in a randomized crossover trial. Each participant completed two 30-min sessions—sensory room use and static seated activities—in a counterbalanced order. Resting vagal activity, vagal reactivity to auditory stimulation, subjective discomfort, mood states, and interoceptive awareness were assessed before and after each session. Vagal indices were derived from respiratory sinus arrhythmia, a heart rate variability measure reflecting parasympathetic cardiac control. Mood was assessed with the Profile of Mood States, Second Edition, and interoceptive awareness with the Multidimensional Assessment of Interoceptive Awareness. RESULTS: Compared to static activities, the sensory room significantly increased resting vagal activity and reduced vagal reactivity to auditory stimuli, indicating enhanced autonomic stability. Although no significant differences were found in subjective discomfort or negative mood states, several aspects of interoceptive awareness, including the Not-Worrying subscale, showed significant improvement following sensory room use. CONCLUSIONS: These findings suggest that sensory rooms may help regulate vagal function and support sensory modulation in individuals with depression, providing a non-pharmacological approach to enhance autonomic regulation and body awareness in psychiatric care.