Coastal entangling net fisheries are globally ubiquitous and have substantial socioeconomic importance, especially in developing nations. Bycatch in coastal nets results in high mortality of vulnerable megafauna including seabirds, marine mammals, and sea turtles, and has led to fisheries closures that incur high social costs. The overlap of intense bottom-set net fisheries with a high-density foraging hot spot of endangered loggerhead turtles at Baja California Sur, Mexico (BCS) produces among the highest recorded megafauna bycatch rates worldwide. From 2007 to 2009, we conducted controlled experiments in partnership with local fishermen at BCS to compare turtle bycatch rates with target catch rates, composition, and market value between conventional (control) and buoyless (buoys removed from float line) nets. In 136 controlled sets of net pairs, buoyless nets reduced mean turtle bycatch rates by 68% while maintaining target catch rates and composition. Our results suggest that buoyless nets offer a promising approach for mitigating sea turtle and potentially other megafauna bycatch while maintaining coastal net fisheries worldwide.