EXAT to seek Cabinet’s approval for 55bn Samui bridge late next year

Bridge expected by 2034

If approved by the Cabinet in 2027, a bridge linking Nakhon Si Thammarat’s Khanom district to Koh Samui in Surat Thani should be completed and opened in 2034, enabling some 7,000 to 8,000 motorists to conveniently drive to the popular resort island.

Surachet Laophulsuk, governor of the Expressway Authority of Thailand (EXAT), unveiled the latest timeline for the 55-billion-baht project, which aims to connect the mainland to Koh Samui to boost tourism and transport.

Study nearly complete

Surachet said the project is still in the final study stage, which has progressed 89.54%. EXAT will hold the third public hearing in November or December this year before concluding the study early next year.

Once the study is finalised, the EXAT board will be asked to approve the project and its environmental impact assessment. Surachet said the plan would then be forwarded to the Cabinet late next year. If the Cabinet approves it in 2027, bidding will begin.

Construction is scheduled to start in 2029 and is expected to take five years, with the bridge opening in 2034.

Expressway and bridge design

The project comprises not only the bridge but also an expressway spanning the coastal districts of Surat Thani and Nakhon Si Thammarat, with a total length of 37.41 kilometres.

EXAT plans to develop the project under a public-private partnership (PPP) system, in which EXAT will oversee construction, while the private sector will manage operation, maintenance, and toll collection.

Infrastructure investment

Given the size of the investment, EXAT will also seek joint participation from infrastructure service providers. The bridge is expected to carry water, electricity, and telecommunications to Koh Samui.

Talks will be held with the Electricity Generating Authority of Thailand, the Provincial Electricity Authority, the Provincial Waterworks Authority, and National Telecom Company regarding joint investment.

Costs and benefits

Surachet estimated that 7,000 to 8,000 vehicles will use the bridge once it opens. The toll fee for a sedan is expected to be around 1,000 baht per trip — higher than the current ferry fare of 550 baht per sedan, plus 170 baht per passenger.

However, he stressed that motorists would save significant travel time, with journeys of just 15 to 20 minutes compared to 1.5 to 3 hours by ferry.

EXAT also estimates the bridge will generate an economic value of 400 billion baht once operational, benefiting southern tourism, particularly Koh Samui, the country’s second most popular island destination after Phuket.

Route details

The expressway will begin at kilometre marker 14+500 of Highway No. 4142 in Tambon Don Sak, Surat Thani, and head east through rubber and oil palm plantations to intersect with Highway 4142 at kilometre marker 35+700 in Tambon Khuan Thong, Khanom district, Nakhon Si Thammarat.

From there, it will run northeast to intersect with rural road No. 4004 and pass more plantations before reaching Ao Prathab, where the bridge will start at Laem Sor cape and connect to Koh Samui. The expressway will end at kilometre marker 9+000 of Highway No. 41740 in Tambon Taling Ngam, Samui district.