# Kathu–Patong expressway: tunnel cut from 17 m to 14 m, Cabinet submission expected in December 2026

> EXAT has sent a revised design for the Phuket expressway to the Ministry of Transport, with the Phase 1 tunnel narrowed from 17 m to 14 m. The revised plan is expected to go to Cabinet around December 2026, construction is planned from October 2027, and opening is targeted for October 2031. The revised design and the new timetable still await a Cabinet decision, and no contractor has been chosen.

The Phuket expressway has a new timetable and a narrower tunnel. On 14 September 2026 the governor of the Expressway Authority of Thailand (EXAT), Surachet Laopoolsuk, gave a progress update on the project, and on 16 September the Deputy Government Spokesperson, Ploytalay Laksameesangchan, set out the same timetable in a Prime Minister's Office release. Phase 1, the Kathu–Patong section, is expected to go to Cabinet for approval around December 2026. Construction is planned to start in October 2027, and opening is targeted for October 2031. The tunnel has been redesigned from 17 m wide to 14 m. Cabinet has not approved the revised design or the new timetable, no contractor has been chosen, and nothing has been built.

## The plan and the dates

The project itself already has Cabinet backing. Thansettakij reported on 26 August 2025 that Cabinet approved EXAT's switch of Phase 1 to Design & Build, with a ceiling of 10,964.77 million baht for construction and supervision; an earlier Cabinet resolution of 18 January 2022 approved the project in its public-private partnership form. What is pending now is the revised design and the new timetable.

According to the release of 16 September, EXAT has submitted the project to the Ministry of Transport with the revised design, and the ministry is asking the agencies concerned for their views. The release sets out the sequence that follows: submission to Cabinet for approval around December 2026; if Cabinet approves, competitive bidding, with a contractor expected around April 2027; land acquisition targeted for completion by January 2027; construction starting in October 2027 and running four years to September 2031; and opening in October 2031. The December 2026 date belongs to the submission, not to the decision — the Nation lists it the same way. The sources also read April 2027 differently: the release and Thai Rath put the contractor there, while Thansettakij, under the heading "civil-works bid, April 2027", puts the opening of the bid there.

The release also gives the purpose in travel time. The journey between Kathu and Patong is expected to fall from about 30 minutes now to 5 minutes through the tunnel, and Phase 1 is expected to carry about 50,000 to 60,000 vehicles a day, including motorcycles. There would be interchanges at Patong and at Kathu. The release describes the existing route as limited by its physical layout and by traffic volume.

Thansettakij, reporting the EXAT governor on 14 September, puts land acquisition for Phase 1 at 99.43% complete, with the rest expected by January 2027. The same report says the civil-works bid is to be open mainly to Thai contractors with tunnel experience, and that foreign contractors may join as a joint venture.

## What would be built, and what it costs

Thai Rath and Thansettakij both reported the EXAT governor's figures on 14 September. Phase 1 is 3.98 km long and costs about 16,757 million baht: about 10,965 million for construction and supervision, and about 5,792 million for land acquisition. EXAT would build the civil works, with private partners joining for operation and maintenance.

Thai Rath sets out the route. It starts at Patong at the junction with Phra Metta Road (ภก.4055), runs about 0.90 km elevated over Phisit Kornkit Road, continues as a 1.85 km tunnel under the Khao Nakkerd hills, and then runs about 1.23 km elevated to Kathu, ending at Highway 4029 (Phra Baramee Road). Thansettakij reports four traffic lanes per direction — two for cars and two for motorcycles, separated by concrete barriers. Both outlets describe the tunnel as the largest in Thailand.

On the width, Thansettakij reports EXAT putting the tunnel at 14.2 m against 17.1 m before, with the length unchanged at 1.85 km. The report attributes the change to construction-material costs, fuel prices, geological studies and earthquake vibration. Thansettakij puts the two phases together at 84,218 million baht.

## The dates have moved since December 2025

On 19 December 2025 Thansettakij reported the EXAT governor saying that Phase 1 — the same 3.98 km and the same 16,757 million baht — would open bidding in February 2026, having slipped from December 2025, which he attributed to normal preparation of bid documents. A winner was expected within about six months, construction was to start within 2026, the build was to take four years, and service was to open within 2031.

Set against that, the September 2026 timetable has the project going to Cabinet in December 2026, a contractor around April 2027, and construction from October 2027. The opening target stayed at 2031 in both. The only design change stated in either record is the tunnel width.

The wider record shows more movement: Thansettakij reported that the first PPP tender drew no bids and that in October 2025 the minister ordered a redesign to a 10 m tunnel and a transfer to the Department of Highways, while the stated opening target moved from within 2030 in May 2025 to within 2029 in September 2025 and to within 2031 in December 2025.

## Phase 2 is further behind

```chart
type: comparison
title: Phuket expressway, Phase 1 and Phase 2 as described by EXAT
hue: cyan
highlight: 0
columns: [Phase 1 Kathu–Patong, Phase 2 Mueang Mai–Kaeo–Kathu]
rows:
  - metric: Length
    values: ["3.98 km", "30.62 km"]
  - metric: Cost
    values: ["฿16,757m", "about ฿67,461m, under review"]
  - metric: Of which land acquisition
    values: ["฿5,792m", "about ฿29,548m"]
  - metric: Tunnel
    values: ["1.85 km, 14 m wide", "1.71 km"]
  - metric: Cabinet submission expected
    values: ["December 2026", "during 2027"]
  - metric: Target opening
    values: ["October 2031", "October 2031"]
source: EXAT governor as reported by Thansettakij and Thai Rath, 14 Sep 2026; Prime Minister's Office release, 16 Sep 2026
```

Phase 2, Mueang Mai–Kaeo–Kathu, is 30.62 km in total — a 24.45 km main line and a 6.17 km spur. Thai Rath describes about 10.42 km at ground level, 1.71 km of tunnel and 18.49 km elevated. The cost is about 67,461 million baht, of which about 29,548 million is land acquisition and about 37,914 million is construction and supervision, and the cost framework is under review. Detailed design is under way, EXAT expects to put Phase 2 to Cabinet during 2027, and the target opening is October 2031, the same as Phase 1. Thai Rath reports that EXAT is asking the Royal Forest Department for permission to use forest land.

## What this means for a Patong or Kathu buyer

Travel between Patong and Kathu today uses the existing road, which the release describes as limited by its physical layout and traffic volume. The planned link would add a route, but the earliest opening date on the table is October 2031, roughly five years away.

The dates have moved repeatedly: a failed tender, three tunnel widths and three historical opening targets since May 2025; the current target is October 2031. The next dated checkpoint is the December 2026 Cabinet submission; if Cabinet approves, the April 2027 contractor date follows.

Land acquisition for Phase 1 is reported at 99.43% complete. Phase 2 is at an earlier stage — its cost is under review, it is expected to reach Cabinet during 2027, and forest-land permission is pending.

## What is not settled

Cabinet has not taken a decision on the revised design or the new timetable, the Ministry of Transport's consultation with other agencies is under way, and the 14 m tunnel design has not been approved. Toll rates are not settled either, and the toll structure has yet to go to Cabinet. Everything after the December 2026 Cabinet step — the contractor, the construction start, the opening — is conditional on that approval.

## Related guides and data

For the area and the purchase itself, see the [[patong-area-guide|Patong area guide]] and the [[phuket-buying-guide|Phuket buying guide]], and current [Phuket asking prices](/prices).