Kathu-Patong Tunnel on Phuket: Cabinet Review Set for Q4 2026

Twenty years of debate, dozens of postponed votes, and billions of baht in feasibility studies later, the tunnel linking Kathu and Patong finally appears close to a real decision. Deputy Transport Minister Sornpetch Boonyamanee has confirmed that the Kathu-Patong Expressway project will be submitted to Thailand's Cabinet for approval in the fourth quarter of 2026.

For anyone who owns property on Phuket's west coast, or is weighing a purchase there, this is a first-tier signal. A route cutting through the island's central mountain ridge would shorten the trip from central Phuket to its main beach resort from 40-50 minutes in traffic down to roughly 15 minutes. This is not just a road project. It is a repricing event for land and condominiums across two districts at once.

Key Facts

• Cabinet review timeline: Q4 2026, according to Deputy Transport Minister Sornpetch Boonyamanee.

• Route: an expressway connecting Kathu and Patong through the mountain ridge currently crossed only by a winding two-lane road.

• Scale: the first phase is a four-lane tunnel roughly 3.98 km long, including a 1.85 km section through Khao Nakkerd, with a budget estimated at 11-16 billion baht, according to Thai media reports.

• Second phase: a 30.6 km elevated expressway between Muang Mai and Kathu, bypassing existing congested roads.

• Post-approval timeline: 12-24 months for tenders, procurement and environmental clearance is typical in Thailand, with construction realistically starting in 2027-2028 and taking around four years once it begins, per The Phuket Express.

• Current travel time between Kathu and Patong reaches 45-60 minutes in high season because of the single, hairpin-heavy Patong Hill pass.

• The project sits within the first phase of the broader Phuket Expressway network and is being reviewed alongside deep-sea port development on the island.

Story and Context

The idea of a tunnel between Kathu and Patong dates back to the early 2000s, when Phuket was riding its first major investment wave after the 1997 crisis. The mountain ridge separating the island's east and west sides has long been Phuket's defining infrastructure headache. The road over Patong Hill is two kilometers of tight switchbacks where trucks and tourist buses regularly overturn.

Over two decades the project has shifted shape more than once. Early versions proposed a straightforward tunnel; later plans introduced an expressway concept with an underground section. Market estimates for construction costs across various versions ranged from 10 to 30 billion baht. Each time, the project stalled at the budget approval stage or was reshuffled along with a new government. Notably, the project has recently been sent back for re-approval by Bangkok, with the tunnel's width trimmed to fit rising cost pressures, a reminder that even a project this close to approval can still see technical revisions.

What is different this time is that Phuket is receiving several major transport upgrades in parallel. A deep-sea port, airport modernization, and light rail proposals are all advancing together, building the kind of critical mass that makes budget committees more willing to greenlight individual pieces once they see the whole picture connecting.

For property owners and buyers, the geography here is very concrete. Kathu sits at the island's center, home to golf clubs, international schools and major shopping malls. Patong is the flagship tourism zone with strong rental demand. Right now a mountain separates these two worlds. If (and when) the tunnel is built, condominiums in Kathu gain direct access to beach infrastructure, while properties in northern Patong end up within walking distance of the tunnel entrance.

History across Asia suggests this kind of infrastructure announcement moves prices before a single shovel hits the ground. Property values within a 2-3 km radius of key transit points have historically risen 15-30% at the approval stage alone, well ahead of construction. That pattern played out around Bangkok's BTS stations between 1999 and 2002, and again around MRT exits along the Sukhumvit Line.

One important caveat: Cabinet approval does not mean construction starts immediately. In Thailand, the gap between project approval and the first pile driven typically runs 12 to 24 months, covering tenders, environmental review and land acquisition. If the Cabinet approves the project in late 2026, construction could realistically begin in 2027-2028, with completion targeted around 2030 for the first phase.

Even so, for investors working on a 5-7 year horizon, this is a genuine window. Land in Kathu remains considerably cheaper than on the west coast. If you are planning a trip to Phuket to inspect properties, it is worth basing yourself in the Kathu area to judge the location relative to the future tunnel firsthand.

Source: The Phuket Express

FAQ

When will the Kathu-Patong tunnel go to Cabinet for approval?

According to Deputy Transport Minister Sornpetch Boonyamanee, the project will be submitted to Cabinet in the fourth quarter of 2026.

How long does the Kathu to Patong drive currently take?

In high season (November to March), the route over Patong Hill takes 45 to 60 minutes. In low season it drops to roughly 20-30 minutes. The tunnel could cut this to around 15 minutes.

Is this a tunnel or an expressway?

Officially it is called the Kathu-Patong Expressway, including a roughly 3.98 km section that runs through the mountain ridge, with 1.85 km passing through Khao Nakkerd. The exact configuration will be finalized after Cabinet approval.

How will the tunnel affect property prices?

Kathu is likely to see the largest gains, since it is currently cut off from the west coast. Market estimates suggest prices within 2-3 km of the tunnel entrance could rise 15-30% once the project is formally approved.

When will construction actually begin?

Even with Cabinet approval by late 2026, construction is expected to start no earlier than 2027-2028. Thailand's standard cycle from approval to groundbreaking runs 12-24 months.

What other infrastructure projects are underway on Phuket?

Deep-sea port development and related transport upgrades are progressing in parallel, and were reviewed during the same site visit by the Deputy Transport Minister.

Is it worth buying property in Kathu now?

Kathu remains one of Phuket's more affordable districts with solid infrastructure already in place, including schools, malls and golf clubs. Tunnel approval would give it a direct link to Patong, meaningfully boosting rental potential.

Could the project be delayed again?

The project's history includes numerous delays spanning more than two decades, and it has already been sent back once for budget-driven revisions. Current political momentum, paired with parallel infrastructure investment across Phuket, makes approval more likely this time, though nothing is guaranteed until Cabinet signs off.

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