Vietnam’s longest sea-crossing bridge takes shape

The project is targeted for completion by late 2028.

The Hon Khoai Island access road project, designed as a four-lane sea-crossing route, broke ground in August 2025 with a total investment of more than VND25.7 trillion (US$989 million).

The project will connect to the end of the Ca Mau-Dat Mui Expressway and feature a 16.5-meter-wide roadway with a designed speed of 80km/h.

Once completed, it will be the longest sea-crossing bridge in Vietnam and the third longest in Southeast Asia.

The project includes nearly 500 bored piles and steel piles, driven 80-110m into the seabed.

Construction has been complicated by the terrain, with numerous underwater scour holes and extremely weak seabed conditions.

Because the work is being carried out offshore, crews have been able to work for only about four months over the past year due to rough seas and strong winds, particularly during the rainy and stormy season.

These conditions have also made it difficult to transport machinery and materials to the construction site.

To cope with the harsh conditions, contractors have mobilized more than 1,000 pieces of equipment and over 2,000 engineers and workers, organizing multiple construction teams to work extended shifts day and night.

According to Army Corps 12, the unit has invested in four high-tech offshore construction machines, each costing around VND1 trillion ($38.5 million), to ensure the project stays on schedule.

Major General Nguyen Huu Ngoc, commander of Army Corps 12 under the Ministry of National Defense, said the project is currently broadly on schedule.

The bridge piers are gradually taking shape using specialized offshore construction technology, demonstrating the military unit’s capacity to build large-span bridges in areas with complex geological conditions while also contributing to the protection of Vietnam’s sovereignty over its seas and islands, he said.

So far, 263 onshore bored piles and 157 offshore bored piles have been completed, while concrete has been poured for 17 piers.

Material supply has also posed a major challenge.

Sand and rock have had to be sourced from multiple localities and transported by sea. While sand supplies are basically sufficient, specialized rock for asphalt concrete and high-strength bridge girders remains in significant short supply, with only a quarry in An Giang Province currently meeting supply requirements.

Alongside the sea-crossing bridge, work on the dual-use Hon Khoai seaport project is also being accelerated.

Efforts to resolve construction bottlenecks and keep the projects on schedule are expected to provide a major boost to Ca Mau, opening up new transport links to attract investment and strengthen regional connectivity.