Lee Kong Chian Natural History Museum

Straits of Singapore


The Straits of Singapore (or Singapore Strait) extends approximately 113 km, from the Straits of Malacca in the west to the South China Sea in the east. At the western entrance, the navigable channel is about 12 km wide and runs through deep water. The narrowest land width is about 5 km although the narrowest navigable breadth is 2.9 km. Mainland Singapore lies to the north of the Straits while most of its offshore islands lies within the Straits itself. Lying south of the Straits of Singapore are the Riau Islands of Indonesia including the two large islands of Bintan and Batam.

The Straits of Singapore is one of the most important maritime passages in terms of usage by commercial vessels and surface naval forces. The Straits provide the shortest sea route between the Indian Ocean (via the Andaman Sea) and the Pacific Ocean (via the South China Sea). This channel is an ancient trade route known for more than a thousand years. The Arabs, Chinese, and Portuguese were the earliest known seafarers to use this strait on their voyages between the Malacca Strait and the South China Sea. The founding of Singapore in 1819 and the developments that followed here and in the region resulted in an increase in shipping traffic in these waters. It became increasingly important to maritime trade following the opening of the Suez Canal in 1869. Since the 1950s, the Straits have become of vital importance to the transport of fuel oil between the Persian Gulf and Japan. Today the Straits of Singapore is one of the world's busiest commercial routes, and a deep water approach to the Port of Singapore.

The current system in the Straits of Singapore is under the influence of major currents driven by trade winds as well as the Asian monsoons, and as such can be highly variable. In addition to tidal forcing, circulation in the Straits is governed by a strong hydrodynamic pressure gradient which reverses direction semi-annually and coincides with seasonal monsoon changes. The tidal variation across the strait also has a significant effect on the water circulation. The substrate of the Straits used to consist more extensively of sand bottom but has been transformed into muddy bottoms due to increased sedimentation. Most of the sand deposits have been exploited for land reclamation.

Despite the busy nature of this channel, the Straits of Singapore possesses rich marine life. Some of the larger marine animals that have been spotted in the waters including the Hawksbill Turtle (Eretmochelys imbricata), Indo-Pacific Humpbacked Dolphins (Sousa chinensis) and Black-tipped Reef Sharks (Carcharhinus melanopterus). It is also home to some of Singapore’s most diverse reefs.

Other Resources

National Library Board Singapore. 2004. Singapore Strait. http://infopedia.nl.sg/articles/SIP_969_2005-01-19.html. (Accessed December 2012).


Chen, M., K. Murali, B. C. V. Khoo, J. Lou & K. Kumar, 2005. Circulation modelling in the Strait of Singapore. Journal of Coastal Research, 21 (5): 960-972.

Leifer, M., 1978. International Straits of the World: Malacca, Singapore, and Indonesia (Volume 1). BRILL. 217 pp.

Tan, H. T. W., L. M. Chou, D. C. J. Yeo & P. K. L. Ng, 2010. The Natural Heritage of Singapore (Third Edition). Pearson Education South Asia Pte Ltd. 323 pp.

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