All transport modes play a role in the country’s transport system and are generally complementary rather than competitive. Road transport is predominant, with a total length of 370,500 km in 2003. The railway system has four unconnected networks in Java and Sumatra that are primarily dedicated to transporting bulk commodities and long-distance passenger traffic.

Sea transport is extremely important for economic integration and for domestic and foreign trade. It is well developed, with each of the major islands having at least one significant port city. The role of inland waterways is relatively minor and is limited to certain areas of Eastern Sumatra and Kalimantan. The function of air transport is significant, particularly where land or water transport is deficient or non-existent. It is based on an extensive domestic airline network where all major cities can be reached by passenger plane.