🔄 Updated 21 Jun 2026
Pa Sak Jolasid Dam is a royally initiated project that dams the Pa Sak River into a vast reservoir straddling Lopburi and Saraburi provinces. The earthen crest runs more than 4 kilometres and you can drive right along it, looking out over water that stretches to the horizon with distant hills beyond. It's an easy day trip from Bangkok — out in the morning, back by evening — but the busiest stretch is the cool season, when the floating train runs for the months it's in service only.
The floating train — the year-end highlight you must book ahead
The floating train is a special sightseeing service run by the State Railway of Thailand (SRT), travelling from Bangkok out to Pa Sak Jolasid Dam. The "floating" part is the stretch where the track crosses the middle of the reservoir — when the water is high you'll see it on both sides of the rails, and from inside the carriage it really does feel like the train is gliding over water. The train slows and stops for about 20 minutes so you can get out and take photos at the mid-dam viewpoint before carrying on to the Pa Sak Jolasid Dam halt.
This service runs in season only, every Saturday and Sunday, roughly November to February, year by year (the latest season ran Nov 2025 – Feb 2026). That's when the weather is cool and the dam's water level looks its best. Running dates and the booking-open date change every year, so check the SRT's announcements or the D-Ticket app again before you go — popular tickets sell out fast, especially the air-conditioned carriages.
Air-conditioned seating (OTOP / JR-WEST)
Air-con carriage with soft, comfortable seats the whole way — good if you're bringing older relatives or kids, since it's a long round trip taking up almost the full day. This carriage fills up first; book it the moment sales open.
Ordinary third class (fan)
Fan carriage with windows you can open to catch the breeze — the classic old-school Thai train feel, and fun for shooting the floating-water views straight out the window. Cheaper too, so it suits a tighter budget or anyone who wants a more rough-and-ready ride.
SRT Royal Blossom premium service
In some seasons the SRT runs its refurbished Japanese-style carriages as a separate special train. Nicely fitted out, wider seats, priced above the regular service, with limited capacity and its own booking. Check the announcement each year first.
A rough schedule for the main train: it leaves Bangkok Station (Hua Lamphong) around 06:00, reaches the mid-dam viewpoint around 09:20 (a stop for photos), then pulls into the Pa Sak Jolasid Dam halt around 10:35. You get the midday hours to walk around and grab lunch before the return train departs around 15:30 and reaches Bangkok around 18:50. Actual times shift with each year's announcement.
How to book without missing out
Tickets go on sale through the D-Ticket system and at railway stations nationwide. The booking-open date is announced in advance, around October. Air-con carriages often sell out on the first day, so if you want one, be logged in and ready before sales open. Fan carriages still give you a chance closer to the travel date.
Want more out of Lopburi? Book tours & activities
Booking online ahead on Klook or GetYourGuide is usually cheaper than the gate and skips the queue. Pick only the experiences you actually want — prices and availability are shown live on each site.
Up on the dam crest — reservoir views you can enjoy by car too
Missing the train is no great loss, because the dam itself is open to visitors every day. Drive in to the crest and you'll find a car park and a long road running along the top, looking out over the wide reservoir and the line of hills, with a cool breeze the whole time. It's a photo spot and an easy place to unwind — locals from Lopburi and Saraburi love coming up here in the evening.
- Crest sightseeing tram — a tram service runs you along the dam crest and back, covering nearly 10 kilometres in total, about 40 minutes a round. A young guide tells the dam's history along the way. Good if you're bringing older travellers or don't want to walk far.
- Mid-crest viewpoint — the spot where the floating train stops for photos. Walk up onto the crest and you'll see water on both sides; early in the morning there's often a light mist and the view is at its best.
- Pa Sak Basin Museum — within the dam grounds, with exhibits on the river-basin area, old artefacts, and the story of how the dam came to be. Open to visitors and good for kids to learn something.
- Luang Pu Yai Pa Sak (Saraburi side) — a large Buddha image below the dam on the Saraburi side, where many people stop to pay respects and ask for a blessing after visiting the dam.
Which month to go, and what the water level is like
The best views and weather come in late rainy / early cool season, around November to February. The reservoir holds full after the rains, so the "floating train" really does look the part, plus the cool weather is just right — which is exactly why the SRT schedules the floating train for this window. Come in the hot season or late in the dry season and the water level drops, exposing more bank and earth, and the view looks fairly different from the photos you see on social media.
Straight talk
Those gorgeous shots of a train running across the water are taken when the reservoir is full and from exactly the right angle. In reality the track sits on an embankment above the water, not submerged — and in a year when the level isn't high, the water can be a fair distance from the rails. Don't expect it to match the photos every day. That said, riding a train along the reservoir is still worth it.
Getting there on your own, and where to park
Driving from Bangkok to Pa Sak Jolasid Dam takes about two and a half hours, via the motorway / Phahonyothin Road through Saraburi into Phatthana Nikhom district, Lopburi. There are car parks around the dam crest and the tram service point. If you take the floating train, you get off at the Pa Sak Jolasid Dam halt, where trams and community stalls are waiting right around midday.
Come by car
The most flexible option — you can pair the dam with the sunflower fields or Lopburi's old town in a single day. Great in the cool season when you want to hit several stops.
Take the floating train
You get the full experience without having to drive, but the timing is fixed to the train. You'll need to book ahead and can only go on Saturdays and Sundays in the cool season.
Want to stay overnight near Lopburi or the dam?
See the Top 10 hotels in Lopburi →