In this exploratory article we investigate how longstanding ‘competitive city’ projects are actively reshaped by recent national security initiatives in urban waterfronts. We argue that port districts in large waterfront cities are becoming critical sites where actors are struggling to further different agendas. While proponents of competitive city projects appear directly concerned with promoting a particular vision of capitalist urban development in contrast to the national security agenda of port and border securitization, we contend that a simple dichotomy between ‘economy’ and ‘security’ cannot capture their complex intermingling. We examine the emergent public discourses of port (in)security in the US and Canada since 9/11, paying particular attention to the convergences between port security and waterfront gentrification initiatives, while also noting conflicts between these agendas. We identify four key areas of change: relations of power in the governance of port spaces, rationales of urban planning decisions, physical redesign of urban port spaces, and conflicts between ‘economy’ and ‘security’. Post 9/11 port security initiatives are sometimes at odds and other times at ease with the competitive city agendas that are readily apparent in urban waterfront redevelopments. Both projects have disturbing implications for social justice in waterfront cities.