Environmental volunteering in nature can bring great benefits to both nature and society which can be enhanced by enlarging and diversifying the pool of people who are engaged as volunteers. Across the world people are becoming used to searching online for commodities and experiences and this is particularly true for younger adults. This is a sector of society that environmental organisations are especially keen to encourage into volunteering. This paper explores what interests communities searching online for environmental volunteering opportunities and how organisations may best match their interests. We first reviewed 1032 scientific papers to identify the key factors that encourage the participation of existing volunteers in environmental projects. We found the most important factor was to tailor projects to the motivations of the volunteers, particularly opportunities for social interaction and learning new skills plus to remove barriers to participation. We then tested what factors motivated the NatureVolunteers’s website online community of 2216 potential environmental volunteers. The online community were on average younger than typical for existing environmental volunteers and their motivations were also different as they were more interested in physical activity and using skills and less in social factors. They also preferred projects which are outdoor based, and which offer close contact with wildlife. Finally, we found that the online community showed a stronger preference for habitat improvement projects over those involving species-survey based citizen science. We assessed whether projects advertised by conservation organisations are meeting the motivations and interests of the NatureVolunteers online community and found some important mismatches. The online community are looking for projects which are more solitary, more physically active and more accessible by organised transport. We conclude that these differences may be widespread beyond the UK and that this merits further investigation. There is great potential for enhancing the benefits of environmental volunteering if conservation organisation can know how to best develop projects that meet the interests of the globally large potential pool of young people searching online for environmental volunteering opportunities.