Considering the lack of nature-based positive psychology interventions (PPIs), the present study examined the effects of Rewild Your Life (RYL), an online intervention programme that challenges users to spend 30 minutes a day in nature for 30 days. Participants who completed RYL (n=35) showed significant increases in mood, well-being, mindfulness and meaning compared to the control group (n=27). The effect was stronger when participants spent at least 30 minutes in nature, and meaning and mindfulness were affected only in "wilderness" but not urban "greenspace" (e.g., parks). Findings emphasise the importance of access to natural spaces, especially considering that people are spending increasing amounts of time indoors and disconnecting from nature, and the importance of increasing access to greenspace is discussed.