Singapore Strait
Busy deepwater strait between Singapore and Indonesia.
Wikipedia / Wikimedia Commons
The Singapore Strait is a 113 km-long, 19 km-wide waterway between the Strait of Malacca to the west and the South China Sea to the east. Singapore lies to the north, and the Indonesian Riau Islands to the south, with the two countries sharing a maritime border along the strait. It includes Keppel Harbour and many small islands, providing the deepwater passage to the Port of Singapore, making it one of the busiest shipping channels in the world.
- length
- 113 km (70 mi)
- width
- 19 km (12 mi)
- location
- Between Singapore (north) and Indonesian Riau Islands (south)
- daily traffic (2017)
- Approximately 2,000 merchant ships
- key feature
- Deepwater passage to the Port of Singapore
- ship class limit
- Malaccamax
Lore & Background
Historical records from the 9th century AD mention a Bahr Salahit or Sea of Salahit, interpreted by some as referring to Singapore, though others generally consider it the Malacca Strait. Early European travellers used 'Strait of Singapore' to refer to the whole or southern portion of the Strait of Malacca. Historians have used the plural 'Singapore Straits' to describe three or four different straits in old texts and maps, including the Old Strait of Singapore, the New Strait of Singapore, the 'Governor's Strait' or 'Strait of John de Silva' (corresponding to Phillip Channel), and the Tebrau Strait. Today, the Singapore Strait refers to the main channel south of Singapore where the international border lies.
Reader's Guide
The Singapore Strait is a critical maritime chokepoint, linking the Strait of Malacca with the South China Sea. Its depth limits the maximum draft of vessels passing through the Straits of Malacca, defining the Malaccamax ship class. The strait was mined by the British during the Second World War. In 2009, the Maersk Kendal grounded on the Monggok Sebarok reef. In 2024, ReCAAP reported targeted stealing of engine spares by pirates as unique to the Singapore and Malacca Straits. In 2025, a major increase in piracy incidents was reported, with over 60% of global piracy occurring in the Singapore Straits. Pilot guides and charts of the straits have been published for a considerable time due to their navigational importance.
Did You Know?
- The Singapore Strait is 113 km long and 19 km wide.
- Approximately 2,000 merchant ships traversed the strait daily in 2017.
- The strait was mined by the British during the Second World War.
- In 2025, over 60% of global piracy incidents occurred in the Singapore Straits.
Frequently Asked Questions
What is the Singapore Strait?
It is a deepwater waterway running 113 km between the Strait of Malacca to the west and the South China Sea to the east, with Singapore on the northern shore and Indonesia's Riau Islands on the southern shore. Its most notable feature is the deepwater channel through Keppel Harbour that feeds directly into the Port of Singapore.
How wide and long is the Singapore Strait?
The strait stretches roughly 113 km (70 miles) in length and spans about 19 km (12 miles) at its broadest point. That generous width allows two-way heavy traffic to flow without creating a chokepoint.
How much shipping traffic passes through the Singapore Strait daily?
Approximately 2,000 merchant vessels cross the strait on a typical day, which places it among the most heavily used shipping corridors on Earth. Much of that flow is funneled through the deepwater passage at Keppel Harbour toward the Port of Singapore.
What is the maximum ship class that can use the Singapore Strait?
Vessels up to the Malaccamax size can transit the strait, a limit dictated by the depth and width constraints of the connected Strait of Malacca channel. Ships larger than that class simply cannot make the passage safely.
Which countries share a maritime border along the Singapore Strait?
Singapore occupies the northern shore while Indonesia's Riau Islands line the south, and the two nations divide a shared maritime boundary running through the waterway. The strait also contains numerous small islands that sit within this jointly bordered zone.
More in Straits, Channels, And Seas 1-24
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