Short answer
On 1 September 2026 Thailand's Cabinet approved three southern double-track railway projects worth 106.798 billion baht: Chumphon to Surat Thani, Surat Thani to Hat Yai Junction, and Hat Yai Junction to Padang Besar on the Malaysian border. The State Railway of Thailand expects to sign contracts in 2027 and finish the work in 2033, according to The Thaiger. Nothing changes on the southern line now, and the reports give no new journey times. The Cabinet also approved a Den Chai to Chiang Mai route in principle.
What the Cabinet approved on 1 September
At a mobile meeting on the Hat Yai campus of Prince of Songkla University on 1 September 2026, the Cabinet approved three southern double-track railway projects worth a combined 106.798 billion baht, the Nation reports. They are Chumphon to Surat Thani at 36.89 billion baht over fiscal years 2026 to 2032, Surat Thani to Hat Yai Junction at 61.53 billion baht over 2026 to 2033, and Hat Yai Junction to Padang Besar at 8.37 billion baht over 2026 to 2031.
The State Railway of Thailand will carry out the work and the government will bear the full cost. The Thaiger reports that the Chumphon section rose from 30.42 billion baht first proposed in 2025, which the government put down to design changes, level crossings, flood prevention and higher material, diesel and land costs.
What was held back and what is only in principle
The Cabinet held back the Hat Yai to Songkhla section, about 29 kilometres and estimated at 15.92 billion baht, until encroachers leave the land, The Thaiger reports. It also approved three more routes in principle, from Pak Nam Pho to Den Chai, from Den Chai to Chiang Mai and from Thanon Chira Junction to Ubon Ratchathani, and told the railway to review their feasibility and prepare business plans.
Prime Minister Anutin Charnvirakul also asked the national planning agency to speed up a study of a rail link from Hat Yai Junction to Sungai Kolok, the Nation reports. No start date was given for any of the in-principle routes.
When a traveller will notice
The State Railway expects to sign contracts in 2027 and finish the work in 2033, according to The Thaiger. Until then the southern line runs as it does now. The Thaiger explains, citing Bangkokbiznews, that on a single track trains must wait at stations for oncoming services to pass, while on a double track they pass without stopping. The reports give no new journey times.
For anyone planning a train to the south in the next few years, the current timetable is the one to use. Check the State Railway of Thailand's timetable and booking page before you travel.
What it means for a Koh Samui trip
Surat Thani is the mainland city from which many travellers continue to Koh Samui by ferry, and the Chumphon to Surat Thani section is the first one listed in the approval. Our Ang Thong Marine Park speedboat tour, from $50 per person, starts with hotel pickup on Koh Samui at about 7:30 to 8:30 am, so the rail works do not touch your tour day.
If you plan to travel overland to the island, tell us your arrival date and we will plan the first tour around it.
Practical checklist
- Use the current State Railway timetable for any train to the south: no change is planned before the work is signed in 2027.
- Treat 2033 as the expected finish, not a promise: the dates come from the railway's plan.
- Do not count on a Den Chai to Chiang Mai rail link: it is approved only in principle.
- Tell us your arrival date at Surat Thani or Koh Samui so we can plan your first tour.
Questions and answers
What did the Cabinet approve on 1 September 2026?
Three southern double-track projects worth 106.798 billion baht: Chumphon to Surat Thani, Surat Thani to Hat Yai Junction, and Hat Yai Junction to Padang Besar, according to the Nation and The Thaiger.
When will the southern double-track railway be finished?
The State Railway of Thailand expects to sign contracts in 2027 and finish the work in 2033, according to The Thaiger. The Nation lists implementation periods ending between fiscal 2031 and 2033.
Will the Chiang Mai rail line be doubled?
The Cabinet approved a Den Chai to Chiang Mai route only in principle and told the railway to review feasibility and prepare business plans. The reports give no start date.
Does this change train journeys now?
No. The reports describe construction plans and give no change to timetables or journey times. Check the State Railway of Thailand's timetable before you travel.