Kathu-Patong Tunnel: Cabinet Approval Expected Q4 2026, Reshaping Phuket's Property Map

Phuket is preparing for its most significant road project in two decades. The Kathu-Patong expressway, featuring a tunnel through the island's central mountain ridge, is on track for Cabinet approval as early as the fourth quarter of 2026. For anyone who owns or is considering property on the western side of the island, this single infrastructure decision is already redrawing the local price map.

Deputy Transport Minister Sornpetch Boonyamanee personally visited Phuket to inspect preparations, with a deep-sea port project reviewed alongside it. Together, the two schemes signal a shift from resort-town status toward a genuine logistics and investment hub.

Key Facts

• Cabinet approval for the Kathu-Patong expressway is expected in Q4 2026.

• Deputy Transport Minister Sornpetch Boonyamanee confirmed the project's priority status during a visit to Phuket in late June 2026, noting detailed studies are nearly complete.

• The route includes a tunnel through the mountain ridge separating Kathu and Patong, expected to cut travel time from today's 40-50 minutes during peak hours to roughly 10-15 minutes.

• The tunnel's diameter has reportedly been revised from 17 meters to 14 meters to improve structural safety and keep costs within the original budget of about 11 billion THB.

• If approved, construction is planned to run for around four years, with Phase 1 (a 4 km elevated route including the tunnel) already moving from planning into the contractor bidding stage.

• A deep-sea port is being developed in parallel, pointing to a broader strategic shift in Phuket's infrastructure planning.

• The Kathu-Patong corridor remains the island's principal transport bottleneck. The single existing road over Patong Hill routinely grinds to a standstill during high season.

Story and Context

The idea of a tunnel linking Kathu and Patong has circulated on Phuket for more than 15 years. Early concepts date back to the start of the 2010s, when traffic over Patong Hill first became a genuine problem for emergency services. Ambulances from Bangkok Hospital Phuket in Kathu have, at times, taken longer to reach Patong than mainland routes twice the distance. The project was shelved more than once, first over budget constraints, then through changes in government, and again in 2020-2021, when the COVID-19 pandemic froze infrastructure planning across the island entirely.

The situation today looks fundamentally different. Phuket has rebuilt its tourism flow, with market estimates putting provincial foreign arrivals close to 10 million per year. That growth is putting sustained pressure on the single mountain crossing. Kathu residents routinely describe a December-to-January morning drive to Patong beach turning into a ninety-minute ordeal.

For the property market, the tunnel changes the equation. Kathu, home to golf courses, international schools and shopping centers, has historically been priced below coastal Patong. A fast link between the two zones creates what's sometimes called a 'bridge effect': housing in Kathu gains access to Patong's infrastructure without its downsides, namely noise, dense construction and rainy-season flooding. A comparable pattern played out in Bangkok after the BTS Skytrain launched in 1999, when condominium prices along the new lines rose 30-60% within the first five years.

One detail that gets less attention is the deep-sea port. Boonyamanee's visit included an inspection of this project alongside the expressway. If built, Phuket would gain direct cargo and cruise routes without transshipment through Bangkok or Surat Thani. For the island's construction sector, that could mean lower material delivery costs, potentially easing upward pressure on new-build pricing.

According to reporting by the Phuket Express, the government has framed the expressway around cost-effectiveness, transparency, safety and accountability, alongside its core goals of easing congestion and strengthening Phuket's transport capacity.

Investors should also weigh the risks. Thai bureaucracy is notorious for the gap between Cabinet approval and an actual construction start. That gap typically runs 12 to 24 months for procurement, tendering and environmental clearances. Phuket's central ridge sits within a protected forest zone, and environmental hearings could extend the timeline further. There is also a track record of resets: progress achieved in earlier rounds has previously been wiped and the project sent back to Cabinet for re-approval. Even so, the fact that the project has reached Cabinet review stage after 15 years of discussion is itself a signal that serious property market players are taking note.

If you're planning a trip to Phuket to view properties, it's worth booking flights early and mapping a route through Kathu to see the current state of the road infrastructure firsthand.

Source: The Phuket Express

FAQ

When will construction of the Kathu-Patong tunnel begin?

Cabinet approval is expected in the fourth quarter of 2026. After that, 12 to 24 months are typically needed for tendering, procurement and environmental clearances. A realistic construction start falls in 2027-2028, with a build period of roughly four years once underway.

How much will travel time between Kathu and Patong be reduced?

Currently the drive takes 40-50 minutes at peak hours, and can exceed an hour during high season. Once the expressway and tunnel open, travel time should drop to 10-15 minutes.

How will the tunnel affect property prices in Kathu?

Historically, new expressway links in Thailand have driven housing price gains of 30-60% within the first five years, as seen along Bangkok's BTS Skytrain corridors after 1999. Kathu, currently priced below Patong, stands to see the largest relative gain.

What is the deep-sea port being built on Phuket?

Alongside the expressway, Thailand's government is developing a deep-sea port on the island, allowing large cruise ships and cargo vessels to dock directly without routing through Bangkok.

Are there risks of delay?

Yes. The route crosses a protected forest zone, which requires environmental approvals. The project has also been discussed for more than 15 years and has been frozen and reset multiple times. The current status is the most advanced it has ever reached.

Who oversees the project?

Thailand's Ministry of Transport oversees the project. Deputy Minister Sornpetch Boonyamanee personally inspected preparations on Phuket in June 2026.

Is it worth buying property in Kathu now, before construction starts?

Infrastructure projects tend to influence prices well before completion. The widest gap between current and future value typically opens up in the window between project approval and the actual start of construction.

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