As the Malacca and Singapore Straits are part of the shortest route between Europe and Asia any impedance to shipping has serious commercial and strategic repercussions. What would be the consequences to tankers and container shipping if access was restricted or prevented? This issue is addressed by examining the costs of using alternative tanker routes to the Straits and the flow-on consequences of removing a mega-hub port from the container-shipping network. The analysis highlights differences between tanker shipping, where the ship itself is the prime unit of interest, and container shipping, where the door-to-door network is of paramount importance.