Phuket Widens Its Main Gateway Road: What 2.27 Km Means for the Island in 2026

Phuket's only road link to mainland Thailand is about to undergo a major overhaul. Provincial authorities have launched a project to widen a 2.27 km stretch of Highway 402, running from Sarasin Bridge (Thepkrasattri Bridge) to the Tha Chatchai checkpoint near the mangrove forests. This is not a cosmetic repair, but an attempt to fix an infrastructure bottleneck that has strained the island for decades.

The project is being overseen by Phuket Governor Nirat Pongsittiworn together with the Department of Highways of Thailand. The Coastal Highway (Route 4302 along Mai Khao Beach) is not part of the plan; this scheme focuses squarely on the island's main entry point.

Key Facts

• Length of the stretch: 2.27 km, from Sarasin Bridge (Thepkrasattri Bridge) to the Tha Chatchai checkpoint

• Route: Highway 402, the primary road connecting mainland Thailand to Phuket island

• Project leadership: Phuket Governor Nirat Pongsittiworn and the director of Phuket's Highway District

• Agency involved: Department of Highways of Thailand

• Coastal Highway (Route 4302) along Mai Khao Beach is excluded from the current widening plan

• Target design: at least four lanes, with options under review including elevated or depressed medians and an overpass segment

• Status in 2026: the project is in the planning and approval stage, with a preliminary expert assessment already underway

Story and Context

Phuket is an island. It is easy to forget that fact until you are stuck in traffic on Sarasin Bridge on a Friday evening. All vehicle traffic between the mainland and the island funnels through a single corridor: Thepkrasattri Bridge (commonly known as the 'new Sarasin Bridge') and the adjoining stretch of Highway 402. The original Sarasin Bridge, built in 1967, has long been closed to cars and turned into a pedestrian landmark. In effect, an island home to more than 400,000 residents, and up to 700,000 during high season when tourists are factored in, relies on a single automotive bottleneck.

Highway 402 is far more than just a road. It is the main transport spine for all of northern Phuket. Trucks hauling construction materials for the island's endless stream of new condominiums, airport buses, tourist taxis and local residents commuting to jobs in neighboring Phang Nga province all funnel through this corridor. Every morning and evening, traffic backs up near the bridge, stretching commutes by 30 to 40 minutes on an ordinary day and up to an hour and a half during holidays.

The stretch between the bridge and the Tha Chatchai checkpoint is exactly where the road narrows and cuts through a protected mangrove reserve. Widening it requires not just engineering work but environmental clearance: mangrove forests are protected under Thai law, and any construction in these zones must go through Thailand's Ministry of Natural Resources.

For property owners and prospective buyers on Phuket, this project carries real practical weight. The northern part of the island, including Thalang district and surrounding areas, has long been seen as less attractive for residential living precisely because of these transport constraints. If the Highway 402 widening moves forward, logistics between the airport, the mainland, and the northern beaches (Nai Yang, Mai Khao) should improve significantly.

Context matters here too: Thai infrastructure projects often take a long road from announcement to completion. Phuket's planned Light Rail Transit system was first discussed back in 2017, and only by 2025 did concrete progress emerge on contracts. Widening a highway is technically a simpler task, but bureaucracy and environmental restrictions could still stretch the timeline out by 2 to 3 years.

One detail worth noting: the Coastal Highway (Route 4302), which runs parallel to Highway 402 along the west coast near Mai Khao Beach, is not included in the current project. That means an alternative entry route to the island remains without modernization for now, though it carries far less traffic than the main corridor.

The pressure on infrastructure is not limited to roads. Industry groups on Phuket have been urging the government to accelerate state spending on essentials including water supply, drainage, electricity and waste management, arguing that demand from the property sector is outpacing current capacity, with calls for additional junctions and tunnels at congestion points. This broader infrastructure strain underscores why the Highway 402 widening matters beyond daily commutes.

It is also worth noting the scale of foreign interest driving this growth: foreign buyers or lessees are estimated to account for around 60% of villa transactions on Phuket, with the share exceeding 90% in Samui and Koh Phangan. That demand is precisely what is pushing local infrastructure to its limits and prompting projects like this one.

For investors planning a property viewing trip to Phuket, it is useful to keep this in mind: if you are arriving from Krabi airport or crossing from the mainland via Phang Nga province, this particular stretch of Highway 402 is what determines whether the journey takes 20 minutes or a full hour.

Source: Bangkok Post

FAQ

Which exact road is being widened on Phuket in 2026?

The project covers a 2.27 km stretch of Highway 402, from Sarasin Bridge (Thepkrasattri Bridge) to the Tha Chatchai checkpoint. This is the main, and effectively only, road connecting the mainland to the island.

When will construction begin?

As of June 2026, the project remains in the planning stage. Exact construction start dates have not been announced. Based on the typical pattern for Thai road projects, it usually takes between 6 and 18 months from approval to the start of work.

Will the Coastal Highway be affected by the widening?

No. The Coastal Highway (Route 4302) is not part of the current project. The widening applies only to the main Highway 402 corridor.

How will this affect property prices in northern Phuket?

Improved transport access has historically pushed up property values in surrounding areas. Northern Phuket, including Thalang, Mai Khao and Nai Yang, could see an added boost, particularly for projects aimed at long-term rentals and residents commuting to the mainland.

Who is responsible for the project?

The project is being led by Phuket Governor Nirat Pongsittiworn, the director of Phuket's Highway District, and the national Department of Highways.

Will there be traffic jams during construction?

Almost certainly. Any road construction on the island's single entry point will inevitably create additional congestion. Past repair works on this stretch suggest authorities typically schedule work at night and during the low season.

Are there alternative ways to reach Phuket?

Yes. Phuket International Airport receives direct flights from dozens of cities worldwide. Ferry services also operate from several points in Phang Nga province, though these are used mainly for passengers rather than vehicles.

Is this project connected to the future light rail system?

There is no direct link. The Light Rail Transit project is a separate initiative with its own route and budget. Both projects, however, aim to address the island's broader transport crisis.

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