Background Entanglement of marine species, particularly endangered sea turtles and cetaceans, in abandoned, lost or otherwise discarded fishing gear is a major conservation concern. Focus of the Article This case study applies Community-Based Social Marketing (CBSM) to reduce marine wildlife net entanglement in the waters surrounding Masirah Island, a marine biodiversity hotspot in Oman. Importance to the Social Marketing Field The study demonstrates the use of social marketing tools in biodiversity conservation, bringing new knowledge to the cross-application of these two fields. Methods The CBSM methodology was applied to select behaviours, identify barriers and benefits, develop strategies and design a pilot study. The responsible disposal of derelict nets in skip bins was selected as the target behaviour, and a mix of behavioural change tools was applied to achieve change: convenience (installation of three skip bins), education (installation of informative signs, distribution of awareness posters, one-to-one engagement with fishers on the beaches), prompts (installation of signs and posters on vessels) and social norms (one-to-one engagement with key influencers and decision makers). The monitoring of behaviour change took place through structured observations over 23 weeks, focussing on the number of nets disposed of in the allocated skip bins. Results Results showed a low level of behaviour adoption rate by skiff and launch vessel fisheries, respectively, 5.36% and 2.58%. Positive results were observed for a short time but did not reach the estimated target value throughout the study period. Recommendations for Research Our pilot study did not lead to broad-scale implementation and we recommend further awareness and engagement with the target audience, trials of various behaviour change tools and increase field monitoring time. We further recommend the application and funding of behaviour change methods applied to fishers with the incorporation of conventional financial, conservation and regulatory tools to support resource management. Limitations Our results show that focussing on specific behaviours with appropriate measurement is both resource and time demanding to solve pressing conservation problems, particularly ones generated by complex industries such as fishing. Various lessons, useful for other social marketers, have been drawn from our evaluation of the overall study.