Kathu–Patong Tunnel: Status, Timeline and What It Could Mean for Karon

The Kathu–Patong tunnel is a planned road link through the hills between Kathu and Patong. As of 23 October 2026 it is not under construction, and its revised design still needs Cabinet approval. The Expressway Authority of Thailand (EXAT) has sent the revised project to the Ministry of Transport and expects the Cabinet to consider it around December 2026, according to reports from September 2026.

Below: what the project is, how the plan has changed, the reported timeline and what it could mean for trips from Karon. Each figure names its source, and where reports disagree we show both versions.

What Is the Kathu–Patong Tunnel?

Officially, it is Phase 1 of the Phuket Expressway project. EXAT’s project website splits the expressway into two phases. Phase 1 is Kathu–Patong, 3.98 km long. Phase 2 is Mueang Mai–Ko Kaeo–Kathu, 30.62 km long.

Most people call Phase 1 “the Patong tunnel”, because a tunnel through the hill is its central section.

EXAT says the expressway is meant to take pressure off Thepkrasattri Road (Highway 402) and Phra Barami Road (Highway 4029). Phra Barami Road is the main road between Kathu and Patong today. EXAT describes it as congested, steep and winding, with frequent accidents.

Where the Route Would Run

Reports from 2025 and 2026 describe the same basic route:

• Patong end: starts at Phra Metta Road, then rises over Phisit Karanee Road on an elevated section of about 0.9 km.
• Tunnel: about 1.85 km under the Khao Nakkerd hills.
• Kathu end: an elevated section of about 1.23 km joins Phra Barami Road (Route 4029).

Where the Project Stands in October 2026

The short answer: it is planned, but not approved in its current form, and building has not started.

• Submitted, not decided. EXAT has submitted the revised project to the Ministry of Transport, which was collecting comments from other agencies in September 2026.
• Cabinet next. Cabinet consideration is expected around December 2026.
• Reported cost. The total investment is reported at 16,757 million baht, including land and construction.
• Land. EXAT’s governor said in June 2026 that land expropriation for the first phase should be fully complete by September 2026. In mid-September, one report gave January 2027 as the target date for finishing land acquisition. Another said 99.43% of the land had been acquired.

There is an earlier Cabinet decision, which can cause confusion. In August 2025 the Cabinet approved a change to how the project is funded and built. The redesigned version now under review still needs its own approval, according to the September 2026 reports. When we checked on 23 October 2026, we found no newer report that changes this.

How the Plan Has Changed Since 2025

The project has been redesigned more than once since 2025. Here is how the main reports describe each change.

Where the reports disagree:

• Who leads the project. The October and November 2025 reports said the Department of Highways would take over from EXAT. The September 2026 reports describe EXAT as preparing and submitting the project. None of the reports we read explains this change.
• Tunnel width. It was 17 m in the earlier design. The minister ordered 10 m in October 2025. EXAT’s 2026 design is about 14 m.
• Lanes. The 2025 design had four lanes in each direction, split between cars and motorcycles. In November 2025 the minister said cars and motorcycles would share lanes. A September 2026 report describes four lanes, two for cars and two for motorcycles, separated by barriers.
• Tolls. The 2025 plan had a flat toll. In November 2025 the minister said the tunnel would be toll-free. In 2026 EXAT proposed lower tolls instead: 20 baht for cars and 10 baht for motorcycles.

One headline in October 2025 said “decades of planning” had been scrapped. The articles themselves describe a redesign, not a cancellation, and the minister said a few days later that the tunnel would be built.

Reported Timeline

These are the targets reported in September 2026, if the Cabinet approves the project:

1. Cabinet consideration: around December 2026.
2. Contractor selection: around April 2027 in one report; around the third quarter of 2027 in another, with tender documents ready by April 2027.
3. Construction: starts in October 2027 and takes about four years.
4. Opening: targeted for October 2031.

Phase 2, the 30.62 km link from Mueang Mai near the airport through Ko Kaeo to Kathu, is still in detailed design. EXAT plans to seek Cabinet approval for it in 2027, also with an October 2031 target.

Treat these dates as targets, not promises. Earlier reports gave completion as October 2028, then 2030. The April 2030 opening the minister mentioned in November 2025 has since moved too.

What It Could Mean for Travel From Karon

Karon is on the west coast, south of Patong. The tunnel’s two ends are in Patong and Kathu. So it matters most for trips that go through Patong and then over the hill to Kathu and the east side of the island.

For that stretch, EXAT says a drive of about 30 minutes between Kathu and Patong would take about five. That is EXAT’s projection for the Kathu–Patong section only. It is not a door-to-door time from Karon.

What the tunnel would not change, based on the reported route:

• The road between Karon and Patong. The tunnel starts on the Patong side, so the coastal leg from Karon is unchanged.
• Trips south and east from Karon that do not pass through Patong.
• Today’s route. Until the tunnel opens, Phra Barami Road remains the main road between Kathu and Patong.

For context, here is how far some Patong destinations are from Ever Prime Residences in Karon, according to the developer’s brochure: Patong Beach 8.9 km, Patong Hospital 10.1 km, Central Patong 11.0 km and Jungceylon Shopping Center 11.1 km. Those trips would not use the tunnel.

If you travel to and from the airport, Phase 2 is the more relevant part of the plan, because it would link Mueang Mai near the airport with Kathu. For the options that exist today, including the Smart Bus route that runs from the airport via Patong to Karon, see our guide to getting from Karon to Phuket Airport.

One practical point: large road projects usually bring roadworks at both ends. If construction starts as planned in October 2027, allow extra time around the Patong and Kathu ends of the route.

This guide makes no prediction about how the tunnel might affect property prices or rents.

How to Follow the Project

The most reliable ways to keep up:

• EXAT’s project website. The Phuket Expressway project site publishes the route, project background and news, in Thai and English.
• The Cabinet decision. Watch for news of the Cabinet meeting expected around December 2026. Major outlets such as Nation Thailand and Bangkok Post usually report Cabinet decisions on infrastructure.

If you are new to the area, our Karon, Phuket area guide covers beaches, daily life and getting around.

Frequently Asked Questions

Has the Kathu–Patong tunnel been approved?

Not in its current form. The Cabinet approved a change to the funding model in August 2025. The redesigned project was expected to go to the Cabinet around December 2026, according to September 2026 reports.

When will the Patong tunnel open?

September 2026 reports give October 2031 as the target opening, with construction from October 2027. Earlier targets of 2028 and 2030 have already slipped.

How long is the tunnel?

The tunnel is about 1.85 km, within a 3.98 km route that includes elevated sections at both ends.

Will there be a toll?

Reports have changed. In November 2025 the minister said it would likely be toll-free. In 2026 EXAT proposed tolls of 20 baht for cars and 10 baht for motorcycles. The final decision is still open.

Will the tunnel make the drive from Karon to Patong faster?

No. The tunnel runs between Patong and Kathu, so the road from Karon to Patong stays the same. It would help on trips that continue from Patong over the hill to Kathu.

Final Takeaway

The Kathu–Patong tunnel has been planned for years and redesigned several times. In October 2026 it is still waiting for Cabinet approval, with a reported target opening of October 2031. If it goes ahead, it would mainly shorten the hill crossing between Patong and Kathu. Trips within Karon and along the west coast would stay the same.

Thinking about living in Karon? Read our Ever Prime Residences project overview, or contact the Ever Prime Residences team to talk about the location and how you would get around the island.

Project status, dates and figures are as reported by the Expressway Authority of Thailand and the news outlets named above, as of 23 October 2026. The revised project has not been approved, and details may change. This article does not predict any effect on property prices or rents.

All project specifications, facilities and distances are taken from the developer’s brochure and are subject to change without notice.

Image note: Images in this article are AI-assisted illustrations, including visuals based on Ever Prime Residences computer-generated renderings. They are not photographs of the completed project.