This research examines the main common characteristics among the contents of five eco-influencer accounts from different Western countries. A quantitative content analysis was performed on 187 Instagram posts published by eco-influencers from the United Kingdom, United States, Belgium, Spain, and Peru. The topics that eco-influencers deal with the most are promoting veganism, spirituality, environmental and political claims, product advertising (their own and third-party), and personal life, generating the most interactions in the accounts. Carousels win on engagement for eco-influencers on Instagram despite videos being sponsors’ favorite format. Both sponsored content and sponsors themselves are well-received, with over half of all posts featuring them. It seems evident that the social capital of influencers encourages environmental commitment, although there is a particular bias to appreciate the person more than their activist message. In light of the results, this research contributes to the social capital theory of influencers by demonstrating that influencers show personal content and emotional appeals, such as activities with their families, personal reflections, and political statements that give them a high sense of authenticity, but which, blurs the barriers between the public and private spheres.