Thailand Plans Free M6 Motorway Trial From December 25, 2026, With Tolls Due in April 2027

A 196 Kilometer Route Leads Thailand's Holiday Road Plans

Thailand plans to open the full 196 kilometer M6 motorway between Bang Pa-in and Nakhon Ratchasima for free trial use from December 25, 2026, with access around the clock before toll collection begins in April 2027. The route is intended to draw traffic away from Phahonyothin and Mittraphap roads during the busy New Year travel period.

Deputy Prime Minister and Transport Minister Phiphat Ratchakitprakarn outlined the preparations during a November 4, 2026, review of three major road projects. Alongside M6, the government is preparing another expressway section above Rama 2 Road and addressing an exit bottleneck on the M82 motorway to Ban Phaeo.

The Department of Highways put M6 civil construction at 99.81% complete and its systems work at 96.42%. Those figures place the project close to completion, while leaving work to finish before the planned December opening and the introduction of full service the following April.

The announcement concerns travel ahead of New Year 2027, called New Year 2570 in Thailand's Buddhist calendar. Thailand's calendar runs 543 years ahead of the Gregorian calendar, so December 2569 is December 2026 and April 2570 is April 2027.

What the December M6 Opening Would Change

M6 provides an alternative for motorists heading toward Nakhon Ratchasima and the Northeast. By moving some vehicles away from Phahonyothin and Mittraphap roads, transport authorities aim to reduce the pressure that builds when people leave Bangkok for family visits and holidays.

The December 25 plan covers the entire motorway and provides free access every day, 24 hours a day. For drivers, that would make the route available throughout the day and night rather than within a limited daily opening window.

April 2027 is the target for full service and toll collection. The November announcement gave no toll rates or detailed traffic rules for the December trial, including permitted vehicle categories, speed limits and any direction restrictions. Those details will matter when motorists choose their route.

An Earlier Holiday Trial Had Different Rules

M6 had already been made available under a separate holiday arrangement for New Year 2026. Siripong Angkasakulkiat, spokesperson for the Prime Minister's Office, announced that arrangement on December 19, ahead of an 11 day free trial running from December 26, 2025, through January 5, 2026.

During that earlier trial, the Bang Pa-in to Pak Chong section changed direction to match the main flow of holiday traffic. It carried outbound vehicles from Bangkok for the first seven days, from December 26 at 12:01 a.m. through midnight on January 1. Inbound travel toward Bangkok began on January 2 at 6 a.m. and continued through midnight on January 5.

Authorities closed that section between 12:01 a.m. and 6 a.m. on January 2 to reverse the traffic direction. The Pak Chong to Nakhon Ratchasima section remained open in both directions throughout the holiday trial.

Access during the earlier period was restricted to vehicles with four wheels, with an 80 km/h speed limit. Seven entry and exit points were listed: Bang Pa-in, Hin Kong, Saraburi, Kaeng Khoi, Pak Chong, Sikhiu and Kham Thale So. Motorists planning travel in December 2026 will need the new operating announcement for the rules that apply to that opening.

M82 Is Open, but Its Exit Needs More Space

The 24.7 kilometer M82 motorway between Rama 2 and Ban Phaeo is already open for free trial use around the clock. It gives drivers another route along a corridor where authorities are working to reduce congestion on Rama 2 Road.

At the Ban Phaeo exit, however, three lanes on the elevated motorway narrow to a single lane. Vehicles arriving across three lanes must merge into one stream before leaving, allowing queues to build even when traffic farther back on the motorway is moving.

Phiphat directed the Department of Highways to accelerate its plan to widen the exit to two lanes. The change would give vehicles two lanes through which to leave instead of one, although traffic would still have to merge from three lanes into two.

No completion date was given for the widening. For motorists using M82 during its free trial, the exit remains a practical consideration when judging how smoothly the journey to Ban Phaeo may run.

Rama 3 Expressway Will Open in Stages

The Expressway Authority of Thailand reported that the 18.70 kilometer Rama 3 to Dao Khanong to Outer Ring Road project was 97.28% complete. Its elevated section along Rama 2 Road is scheduled to open for trial use in December 2026.

Construction under contract 3, which includes the toll plaza, is being accelerated. Phiphat set a separate target of mid-2027 for opening the outbound route from Thotsamarachan Bridge through M82 to Ban Phaeo.

That connection is intended to give outbound traffic a route linking the bridge, the expressway network and M82, helping ease the load on Rama 2 Road. Its opening depends on completing the relevant connecting works, rather than simply finishing an isolated stretch of elevated roadway.

The broader Rama 3 expressway project is expected to be fully completed by late 2027. The schedule therefore has three stages: a December 2026 trial on the elevated Rama 2 section, the outbound connection targeted for mid-2027, and completion of the wider project later that year.

Why the Remaining Work Matters

M6's two progress figures measure different parts of the job. Civil works cover the physical construction of the road and its structures. Systems work concerns the equipment and controls needed to operate the motorway.

At 99.81%, M6 civil works had 0.19 percentage points left to reach completion. Systems work, at 96.42%, had 3.58 percentage points remaining. The figures show why a motorway can look almost finished while still requiring operational preparations before a broader opening.

Phiphat instructed the agencies involved to check construction, safety systems and traffic signs, and to announce opening arrangements in advance. He also stressed that construction must meet safety standards as agencies push to bring sections into service.

Drivers need both a usable road and clear instructions about where they can enter, which direction they can travel and where works remain. The earlier M6 trial, with its overnight closure to reverse traffic, shows how operating arrangements can shape a journey as much as the route itself.

The Dates for Drivers to Watch

The programme stretches across two holiday seasons and several stages of construction. The main dates are:

• December 26, 2025, to January 5, 2026: An earlier free M6 holiday trial operated with vehicle restrictions and changes in traffic direction.
• November 4, 2026: Phiphat reviewed preparations for M6, M82 and the Rama 3 expressway project.
• December 2026: Trial use is planned for the elevated Rama 2 section of the Rama 3 expressway project.
• December 25, 2026: Free trial use of the full M6 route is scheduled to begin, with access 24 hours a day.
• April 2027: M6 is scheduled to begin full service and toll collection.
• Mid-2027: The outbound connection from Thotsamarachan Bridge through M82 to Ban Phaeo is targeted to open.
• Late 2027: The wider Rama 3 expressway project is expected to be completed.

M82 is already available for free trial use, while the Ban Phaeo exit widening remains a task the Department of Highways has been told to accelerate. Its completion will be especially relevant as authorities prepare the connected outbound route.

Two Corridors, Different Immediate Priorities

M6 and the Rama 2 projects serve different journeys. M6 is intended to ease travel toward the Northeast by taking vehicles off Phahonyothin and Mittraphap roads. M82 and the Rama 3 expressway works focus on providing alternatives and connections along the Rama 2 corridor.

For M6, the immediate priority is preparing the full route for continuous trial access before the New Year rush. Along Rama 2, authorities must also resolve how traffic moves between elevated sections, connecting roads and exits. The three projects share a holiday deadline, but the work needed to make each journey smoother is different.

Key Points

• The full 196 kilometer M6 is scheduled to open for free trial use on December 25, 2026, around the clock.
• M6 toll collection and full service are planned for April 2027.
• The earlier December 2025 to January 2026 M6 trial had specific vehicle, speed and direction restrictions.
• M82 is already free during its trial, with a widening planned at the congested Ban Phaeo exit.
• The elevated Rama 2 expressway section is scheduled for trial use in December 2026.
• The outbound bridge to Ban Phaeo connection is targeted for mid-2027, ahead of expected completion of the wider Rama 3 project late that year.