The concepts of ‘port security’ and ‘maritime security’ are interdependent in practice, and the contemporary maritime security dispensation was triggered by the 11 September 2001 (9/11) incident in New York which, ironically, took place on land. The international community and by extension all maritime security stakeholders were ferociously challenged to rethink their strategies and redefine their functional roles with respect to maritime security. The understanding was that any security regime elastic enough to accommodate maritime terrorism with all its facets would obviously accommodate minor related security threats as well. Spearheading this whole effort was the US, followed by Europe. In order to ensure sustainable port security through appropriate investments, it is useful to understand which stakeholders within the maritime industry will bear the costs or stand to benefit relative to such investments, and questions arise as to how best to proceed with an analysis in this regard. This article thus discusses port security investment issues in the post 9/11 era, drawing extensively from US and European secondary sources, although issues concerning Africa and elsewhere are also briefly considered. It discusses the raison-d’être of port security investments from the general and economic perspectives with illustration from the estimated costs and impact of some major global, regional, national and private security measures and initiatives. The article concludes that port security investments are of benefit to ‘everyone’ and while some stakeholders may try to offset the costs, everyone somehow pays, or at least has to bear the costs as well.