Purpose – The purpose of this paper is to use an eco-friendly service concept framework to demonstrate the effect of credible eco-certification signaling. Design/methodology/approach – The authors examine a cross-sectional data set consisting of 2,481 hotel sites across the US. The authors measure the performance of the operations component of eco-friendly service by operations-driven resource efficiency (ODF), and the performance of the marketing component by customer-driven resource efficiency (CDF). A series of multivariate regressions compare these two resource efficiency measures between credibly eco-certified hotel sites and others. Findings – The results indicate that credible eco-certifications achieve the signaling effect. Eco-certified hotels outperform others in both ODF and CDF measures; and eco-certified hotels still achieve higher CDF after controlling for ODF. Practical implications – The findings suggest that eco-friendly service design requires not only eco-friendly operations but also a built-in credible signaling mechanism. This mechanism engages the customers in eco-friendly service coproduction and in doing so integrates the operations and marketing components of eco-friendly service strategy through eco-certifications. Originality/value – This study is among the first to demonstrate empirically the signaling effect of credible eco-certifications in services. It increases understanding of eco-friendly service design and delivery by exploring the role of credible eco-certifications in linking customer benefits with the service organization’s strategic intent.