There is potentially an infinite number of maritime shipping routes that can be used for commercial circulation, but the configuration of the global system is relatively simple. The main axis is a circum-equatorial corridor linking North America, Europe, and Pacific Asia through the Suez Canal, the Strait of Malacca, and the Panama Canal. These routes are supporting the bulk of the traffic, but numerous other routes exist (namely for coastal shipping), depending on the origin and the destination of the maritime shipment. Transatlantic and transpacific traffic concerns a wide variety of ports, so there are numerous routes, most of them having a path along the great circle. Trans-Indian ocean traffic is dominantly intermediary traffic between Pacific Asia and Europe, implying a series of more clearly defined routes, namely between the Strait of Malacca and Bab el-Mandab.
Maritime routes are a function of obligatory points of passage, which are strategic locations that act as chokepoints. Physical constraints (coasts, winds, marine currents, depth, reefs, ice) and political borders also play an important role in shaping maritime routes. As a result, maritime routes try to follow the great circle distance. Core routes are those supporting the most important commercial shipping flows servicing major markets. Secondary routes are mostly connectors between smaller markets.
In part due to geography, geopolitics, and trade flows, specific locations play a strategic role in the global maritime network. They are labeled as chokepoints and can be classified into two main categories:
- Primary chokepoints. The most important since they offer limited cost-effective maritime shipping alternatives, which would seriously impair global trade. Among those are the Panama Canal, the Suez Canal, the Strait of Hormuz, and the Strait of Malacca, which are key locations in the global trade of goods and commodities.
- Secondary chokepoints. Support maritime routes that have alternatives but would still involve a notable detour. These include the Magellan Passage, the Dover Strait, the Sunda Strait, and the Taiwan Strait.