Globally, an estimated 100 million sharks and rays are killed each year—about 7% of the population. The rate of loss exceeds growth rates and explains ongoing global population declines. In March 2013, the Sixteenth Conference of the Parties of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) voted to list five shark species and all manta rays on CITES Appendix II, a key step toward regulating their commercial trade. Much of the trade originates from Indonesia, the world’s largest shark and ray fishery. Following the CITES listing, the Indonesian government worked with WCS and partners to better understand the current trade and to initiate a policy process to regulate it. In early 2014, Indonesia declared mantas as a protected species and banned all fishing and commercial trade: a significant milestone. WCU is a WCS-facilitated partnership of government agencies, civil society organizations, volunteer informant networks, and the media, that has been working since 2003 to combat trafficking of tigers, orangutans, and other protected species in Indonesia. This has resulted in the successful prosecution of more than 300 poachers and traffickers. With key support from WCU, the first ever arrest of a manta ray trader under the new regulation was made in August 2014. A series of arrests have since been made. The initial successes, achieved in only a few months, demonstrate the viability of this project’s approach. The challenge now is to shut down the trade across Indonesia.