Combating piracy at sea and apprehending pirates have been a long-standing problem for the global community. Increasing acts of piracy off the coast of Somalia have prompted the UN Security Council to intervene in the matter. The Council, through several resolutions, has authorised states to take action against Somali pirates in the territorial waters and land territory of Somalia and recently adopted a resolution urging all states to fully implement relevant international conventions in their domestic legal systems. However, despite the Security Council's intervention in the matter most states are still reluctant to prosecute Somali pirates in their domestic courts. Considering the most recent Security Council resolution and existing international law, this article examines whether there is an international obligation to criminalise piracy under domestic legal frameworks and to prosecute pirates in domestic courts. It submits that existing international law arguably imposes an obligation to prosecute pirates, at least in certain circumstances, and the recently adopted Security Council resolution reinforces this obligation.