Phuket Kathu-Patong tunnel plan heads to Cabinet

The Expressway Authority of Thailand (EXAT) is seeking Cabinet approval by about December 2026 for a 16.757 billion baht expressway linking Kathu and Patong, including what it says will be Thailand's largest mountain tunnel.

If approved, construction on the first phase of the Phuket Expressway is due to begin in October 2027, with the road opening targeted for October 2031. EXAT says the route would cut the Kathu-Patong journey from around 30 minutes to five minutes.

For residents, visitors and workers in Phuket, the proposed road could offer a faster alternative to the steep and often congested existing routes between Patong and central Phuket. However, the scheme remains subject to Cabinet approval, land acquisition and the contractor tender process.

Tunnel and elevated road between Patong and Kathu

EXAT governor Surachet Laopoolsuk said the first phase is intended to address travel difficulties created by the mountain range separating Kathu and Patong.

The 3.98km route would comprise elevated sections and a 1.85km tunnel through Nakkerd Mountain. It would begin near the Phra Metta Road, or PK.4055, intersection at km 0+350 on the Patong side, run on an elevated road for about 0.90km over Phisitkarnnee Road, then emerge onto a further 1.23km elevated section near Phra Baramee Road, or Highway 4029, in Kathu.

The tunnel has been redesigned, which EXAT says would make it the country's largest tunnel, with four lanes in each direction: two for cars and two for motorcycles, reflecting travel patterns in Phuket.

The plan includes grade-separated interchanges at both Patong and Kathu. EXAT has submitted the scheme to the Ministry of Transport and is consulting relevant agencies. Land acquisition is expected to finish by January 2027, while contractors could be selected by April that year.

Of the total budget, 5.792 billion baht is allocated for land acquisition and 10.965 billion baht for construction and supervision. EXAT would fund civil works, while private investors would co-invest in operations and maintenance.

Proposed tolls cut from earlier rates

EXAT has revised proposed tolls under the government's cost-of-living policy. Motorcycles would pay 10 baht rather than 15 baht; cars 20 baht instead of 40 baht; six- to ten-wheel vehicles 40 baht rather than 85 baht; and vehicles with more than 10 wheels 60 baht rather than 125 baht.

The authority expects 50,000 to 60,000 vehicles a day, including motorcycles, when the first phase opens. Traffic is expected to rise once the second phase is complete.

Second phase would extend network north and east

Phase 2 would run from Muang Mai through Koh Kaew to Kathu, linking central and eastern Phuket to the network. Its 30.62km length includes 24.45km of main road and a 6.17km spur line, at a preliminary cost of 67.462 billion baht.

That estimate includes 29.548 billion baht for land acquisition and 37.914 billion baht for construction and supervision. EXAT is designing the project, pursuing Royal Forest Department permits and expects to seek Cabinet approval in 2027.

Construction is targeted for October 2028 and would take three years, allowing an October 2031 opening alongside Phase 1. The route would include 10.42km at ground level, 18.49km elevated and 1.71km in 11.68-metre-wide tunnels.

It would start at Highway 4026, head south through Muang Mai and join Highway 4029. A spur from the Ma Nik 2 interchange would end at the Bang Khu interchange on Highway 4024. A distance-based closed MTC/ETC toll system is planned, along with a 13-rai outbound airport service area at km 3+900 and a spur-line rest stop at km 16+400.

Pictures courtesy of ThaiRath

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15 September 2026