(Detailed PDF Map)
Source: adapted from Drewry Shipping Consultants and web sites of port authorities.
Note: Transshipment figures are an average over the 2007-2012 period to account for missing data and annual fluctuations in transshipment volumes.

World's Main Intermediate Hubs and Markets, 2007-12

With the growth of long distance containerized trade, intermediate hubs grew in importance in helping connect different systems of maritime circulation. They tend to be located along the main circum-equatorial maritime route that goes through Panama, the Strait of Malacca, Suez and Gibraltar. Intermediate hubs usually have a low maritime deviation and many provide connectivity between north-south and east-west shipping lanes. Transshipment incidence is the share of the total port throughput that is "ship to ship", implying that the final destination of the container is another port. The higher it is, the more a port can be considered as a transshipment hub. For ports with low transshipment incidence (less than 25%), transshipment is an incidental activity, while ports having a transshipment incidence above 75% can be considered as "pure" transshipment hubs.

Transshipment emerged in the 1970s as trade with Asia increased but volumes were not sufficient to justify direct connections to many ports. Ports such as Singapore, Busan, Tokyo and Kaohsiung emerged as the first transshipment hubs. This eventually led to the setting of pure transshipment hubs at key locations along major shipping routes, such as Colombo, Salalah, Gioa Tauro, Algeciras and Kingston. The emergence of major intermediate hubs favored a concentration of large vessels along long distance high capacity routes while smaller ports could be serviced with lower capacity ships. Economies of scale over long distances are thus reinforced, permitting liner services that would otherwise be economically unfeasible. However, there is a limit to the hub-and-spoke network configuration and consequently also to the size of the vessels being deployed on the trunk routes.

Seven major transshipment markets accounting for the bulk of the transshipment activity. They are referred as markets since transshipment is an activity that is not tied to a specific port, unlike gateway traffic linked with a hinterland and inland freight distribution. Therefore, transshipment hubs compete for the traffic related to a region / market. Geography plays an important role in the setting of a transshipment market, which is often at the crossroads of north / south shipping routes and where there is a bottleneck:

• The world's most important intermediate hub is Singapore where 85% of the traffic is transshipment, which accounted for more than 26.9 million TEUs of transshipped containers in 2012. The major Asia - Europe shipping lanes are constrained to pass through the Strait of Malacca, which incited to setting of an adjacent transshipment hub competing with Singapore; Tanjung Pelepas.
• There can be also a shift in the transshipment dynamics due to the changing commercial  environment. For instance, transshipment incidence levels in the Japanese ports of Tokyo and Yokohama used to be in the 20% range, but have declined to less than 10% as Japan was losing its role as a manufacturing center with many transshipment activities shifting to Korea or China.
• The Mediterranean has only two points of entry (Suez and Gibraltar), both of which have significant transshipment activity, as well as ports that are at the center of the basin (e.g. Marsalokk and Gioa Tauro).
• Although the Caribbean has a large exposure on the Atlantic side, it has one outlet for the Pacific; the Panama Canal which has significant transshipment activities both on the Atlantic and Pacific coasts. The Caribbean generates limited cargo demand, but neighboring regions are substantial generator of traffic, some of which is being transshipped in the region (East and Gulf cost of the United States, Central America and northern South America).
• The North Sea and the Baltic are another transshipment market, but of lower incidence since the Baltic generates less freight volumes. Since the Baltic is a dead-end, it is subject to tail-cutting with its ports serviced by feeder services from northern Europe (e.g. Antwerp, Hamburg).