Tip · Do the cave first, mid-morning. That's when the sun drops a shaft of light straight through the roof of Tham Khao Luang onto the Buddha images, and you beat both the heat on the palace hill and the tour vans coming up from Hua Hin.
Almost every foreign visitor drives straight past Phetchaburi, usually asleep on a minivan to Hua Hin. Thais know better. They stop for the desserts.
Phetchaburi (Phetburi, if you're saying it out loud) is a provincial town about two hours south of Bangkok, on the road and rail line that carries on down to Hua Hin and the rest of the south. It isn't a beach town and it isn't a field of ruins. It's a working Thai town that happens to have a royal hilltop palace, a cave full of Buddha images, a couple of centuries of history along its river, and a dessert tradition good enough that people drive down from Bangkok just to eat. It is, in my opinion, one of the day trips out of the city I most often recommend, and one almost nobody books.
Getting there
The train is the nice way to do it. Services leave Krung Thep Aphiwat (the big new station at Bang Sue) several times a day and take roughly two and a half hours down the southern line. It's cheap, it's flat farmland most of the way, and it drops you in the middle of town. Minivans from Bangkok are a little faster at around two hours and run more often, but they're minivans.
If you're already heading to Hua Hin or Cha-Am, note that Cha-Am is actually in Phetchaburi province: the town is only 30 to 40 minutes north, so it slots in as a stop on the way rather than a separate trip. Once you're there, the old town is walkable, and for the cave (a few kilometres out) grab a motorbike taxi or a tuk-tuk and have it wait for you.
Book transport
Getting to Phetchaburi
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Khao Wang, the palace on the hill
The landmark you'll see from anywhere in town is Phra Nakhon Khiri, which everyone calls Khao Wang, or Palace Hill. King Mongkut (Rama IV), the astronomer king, built it in 1860 as a summer retreat, and it fits the man perfectly: a white palace in a hybrid Thai and European style, an observatory tower for his telescopes, and temples and chedis spread across three wooded peaks. A funicular runs up one side (150 THB gets you the ride both ways and the palace museum), or you can walk if the heat isn't already winning.
Two warnings. The hill is exposed and gets brutally hot by midday, so go in the morning. And it is full of macaques, who are organised, unafraid, and will go through your bag the moment you stop paying attention. Keep any food out of sight and hold onto your sunglasses. The reward at the top is the view: the town laid out below, the temple roofs, and the flat green run of the province out toward the Gulf.
Tham Khao Luang, the cave of Buddhas
A few kilometres outside town is Tham Khao Luang, and it's the thing I'd send you to if you only did one. You climb down into a limestone cavern that opens up under a natural hole in the roof, and inside are more than a hundred and eighty Buddha images arranged in the light. Mid-morning the sun comes through that hole and drops a clean shaft of light straight onto the figures. It's the photo everyone comes for and it genuinely earns it. Both Rama IV and Rama V had shrines placed down here, so it's a royal site as much as a natural one. More monkeys at the entrance, same rules as the hill.
The old town
Back in the centre, Wat Mahathat Worawihan is the working temple you can't miss: five white prangs you can see over the rooftops from most of the town. Down toward the river, Wat Kamphaeng Laeng is older and quieter, a set of Khmer laterite towers from when this was the edge of the Angkorian world. The stretch of old town along the Phetchaburi river between them is a good slow walk, full of old shophouses, and it's where the food is.
The food is the actual reason to come
Phetchaburi runs on palm sugar. It's tapped from the toddy palms standing in the fields all around the town, and it ends up in nearly everything, sweet and savoury. The old town has been making khanom, Thai sweets, for the royal court for a couple of centuries, and it still does. Look for khanom mo kaeng, a dense baked mung-bean and coconut custard that Phetchaburi is famous for, sold in slabs from shops that have made nothing else for generations.
If you come in the hot season, this is one of the few places that does khao chae properly: chilled rice in cold jasmine-scented water, eaten with a tray of small fried and stuffed side dishes. It started as a royal hot-weather dish and Phetchaburi kept it. It sounds strange and it's one of my favourite things to eat in Thailand when the temperature is stupid.
The province keeps going
Like a lot of Thai provinces, the town is the first page, not the whole book. Phetchaburi runs west into Kaeng Krachan, the largest national park in the country, a stretch of forest and a big reservoir along the Myanmar border with elephants, hornbills, and morning mist off the water. That's a trip of its own, and one that needs your own wheels and an early start rather than a town day out. But it's worth knowing that the dessert town is also the front door to some of the wildest country left in central Thailand.
When to go, and how long
The cool season, November to February, is the comfortable time, mostly because Khao Wang is no fun to climb in the heat. March to May is punishing on the hill but it's the season for khao chae, so pick your priority. The green season is fine and quiet.
You can see Phetchaburi properly in a single full day from Bangkok: the cave in the morning, the hill and the town temples before lunch, and the rest of the afternoon eating your way along the old town. Give it a night if you'd rather go slow, or if you're carrying on south and want to break the journey.
If you are heading down the coast from here, the Hua Hin, Cha-Am and Prachuap Khiri Khan guide picks up exactly where Phetchaburi leaves off. And if this is still early in your planning, the best time to visit Thailand has more on the seasons and what they do to a trip.
Hero photo: Phra Nakhon Khiri by Preecha.MJ, CC BY-SA 4.0, resized.