Inland waterways—rivers and lakes—are the main channels of transportation. No single railroad runs the full length of the country, and paved highways are few and short. Lack of adequate transportation is a major problem affecting the development of the DROC's vast area. While the rivers, particularly the Congo and its tributaries, are mostly navigable, they are blocked at various points from through navigation by cataracts and waterfalls, making it necessary to move goods by rail or road between the navigable sections. Principal river ports are Kinshasa, Ilebo, Mbandaka, Kisangani, Kalemie, Ubundu, and Kindu. A total of 15,000 km (9,321 mi) of river and lake waterways are in service. The chief seaport and only deepwater port is Matadi on the Congo River, 148 km (92 mi) from the Atlantic Ocean. Other seaports include Boma and Banana, also on the Congo below Matadi. The Zaire Maritime Company is the national shipping line.
In 2002, there were about 157,000 km (97,560 mi) of roads, but most of this was mere track. One of the major routes was from Kinshasa to Lubumbashi. The road network is in a state of deterioration. Motor vehicles in 2000 included 172,900 passenger cars and 41,600 commercial vehicles.
There were 5,138 km (3,192 mi) of railway in 2002. Among the most important internal links are Lubumbashi-Ilebo, Kingala-Kindu, Ubundu-Kisangani, and Kinshasa-Matadi. In the early 1980s, the Kinshasa-Matadi line was extended by a Japanese company. A road and rail bridge across the Congo River at Matadi was completed in 1983. The southeastern network connects with the Angolan and Zambian railroad systems. In 1974, all railroads were consolidated under a single state-controlled corporation, SNCZ.
Air transport has become an important factor in the country's economy. The DROC has five international airports—N'Djili (Kinshasa), Luano (Lubumbashi), and airports at Bukavu, Goma, and Kisangani—which can accommodate long-distance jet aircraft. Altogether, were are 232 airports, airfields, and landing strips in 2001, 24 with paved runways. The national airline, Air Zaïre, was organized in 1961 and has flights to European and African cities, as well as within the country. Zaïre Aéro Service and Scibe Airlift Cargo Zaire also offer domestic and international flights. In 1997, 262,000 passengers were carried on scheduled domestic and international airline flights.