The vast size and highly unregulated nature of the world's waterways have made the maritime environment an attractive theater for perpetrators of transnational violence. Both piracy and sea-borne terrorism have become more common since 2000 due to the global proliferation of small arms as well as growing vulnerabilities in maritime shipping, surveillance, and coastal and port-side security. In addition to massive increases in maritime traffic, pirates have profited from increasingly congested maritime chokepoints, the lingering effects of the Asian financial crisis, and weakened judicial and governmental structures. Some analysts also fear that terrorists may soon exploit the carefully calibrated freight trading system to trigger a global economic crisis, or use the container supply chain to transport weapons of mass destruction. While speculation about an emerging tactical nexus between piracy and terrorism is complicating the maritime threat picture, credible evidence to support this presumed convergence has yet to emerge. Since 2002, the United States--one of the world's principal maritime trading states--has spearheaded several important initiatives to improve global and regional maritime security. Although an important contribution, the author urges policymakers to consider four additional measures to better safeguard the world's oceans: helping to further expand the post-9/11 maritime security regime; conducting regular and rigorous threat assessments; assisting with redefining mandates of existing multilateral security and defense arrangements; and encouraging the commercial maritime industry to make greater use of enabling communication and defensive technologies and accept a greater degree of transparency in its corporate structures.