The Sea Shepherd Conservation Society engages in various demonstrations, campaigns, and tactical operations at sea and elsewhere, including conventional protests and direct actions to protect marine wildlife. Sea Shepherd operations have included interdiction against commercial fishing, shark poaching and finning, seal hunting and whaling. Many of their activities have been called piracy or terrorism by their targets and by the ICRW. Sea Shepherd says that they have taken more than 4,000 volunteers on operations over a period of 30 years.

The Sea Shepherd Conservation Society (SSCS) is a non-profit, marine conservation activism organization based in Friday Harbor on San Juan Island, Washington, in the United States. Sea Shepherd employs direct action tactics to achieve its goals, most famously by deploying its fleet of ships to track, report on and actively impede the work of fishing vessels believed to be engaged in illegal and unregulated activities causing the unsustainable exploitation of marine life.