What is Tuol Sleng?
Tuol Sleng was a high school in Phnom Penh until the Khmer Rouge took power in 1975 and turned it into Security Prison 21 (S-21), a secret centre for interrogation and torture. Thousands of men, women and children were imprisoned here, and almost all of them were killed, most at the Choeung Ek execution site outside the city. Only a handful survived.
Today it's the Tuol Sleng Genocide Museum, part of a UNESCO World Heritage listing of Cambodian memorial sites. The four school buildings have been left much as they were found: the cells, the interrogation rooms, the barbed wire, and the rooms of prisoner photographs taken by the Khmer Rouge as they registered each person.
Tickets
Pay at the gate, usually in US dollars. There's rarely a long ticket line, so you don't need to book online. Resellers mostly sell transport and guide packages that combine S-21 with Choeung Ek.
Get the audio guide
The audio guide, available in many languages, includes testimonies from survivors and former guards and takes you through the site building by building. It transforms the visit, and it's the best few dollars you'll spend in Phnom Penh.
🎟️ Skip the ticket line
Check the crowds, find the best time slot, and book through our authorised partner.
How busy is Tuol Sleng?
Our crowd data shows the museum is equally busy every day of the week. The pattern is set by the time of day: quiet at 8 am, then busy from about 9 am to 4 pm as tuk-tuk tours and groups combine it with the Killing Fields.
Crowds by day and time
From the typical weekly visitor pattern for Tuol Sleng Genocide Museum, based on Google’s popular-times data.
Least busy time
Sunday, 8-9 am
Busiest time
Sunday, 9 am-5 pm
Combining it with the Killing Fields
Most visitors pair Tuol Sleng with the Choeung Ek Killing Fields, about 15 km south of the city, where most S-21 prisoners were executed. They're separate sites with separate tickets.
- Tuol Sleng first, at 8 am, then Choeung Ek. This follows the prisoners' story in order and gets you to S-21 before the crowds.
- Or Choeung Ek first, early, then Tuol Sleng in the afternoon. Choeung Ek is outdoors, so it's cooler early.
- A tuk-tuk for half a day is the easiest way to do both. Agree the price and the waiting time upfront.
Doing both in one day is emotionally heavy. Many people prefer to leave the afternoon free.
What to expect
A place of mourning
S-21 is a site of genocide. Dress respectfully (shoulders and knees covered), keep your voice low, and don't smile or pose for photos. Some rooms contain disturbing images.
- Building A: the interrogation rooms, each with a metal bed and a photograph of what was found there.
- Building B: the rooms of prisoner portraits, the most haunting part of the museum.
- Building C: the brick and wooden cells, still wrapped in barbed wire.
- Building D: exhibits on the Khmer Rouge regime and its aftermath.
Getting there
Tuol Sleng is on Street 113 in central Phnom Penh, about 10 minutes by tuk-tuk from the riverfront and the Royal Palace. PassApp and Grab are cheap and easy.
Mistakes to avoid
- Skipping the audio guide to save $5.
- Arriving at 10 am with the tour groups.
- Dressing for the beach.
- Taking selfies or posing for photos.
- Bringing young children.
Is Tuol Sleng worth visiting?
Yes. It's painful, but it's essential to understanding Cambodia's recent history and the people you'll meet across the country. Go at 8 am, take the audio guide and give yourself time afterwards.
Pair it with
- The Choeung Ek Killing Fields, about 30-40 minutes away by tuk-tuk.
- The Royal Palace and Silver Pagoda, a calmer afternoon visit.
- The National Museum of Cambodia, next to the Royal Palace.
Check today's crowd forecast for Tuol Sleng.
FAQs
How much is the Tuol Sleng Genocide Museum?
+
About $5 for foreign adults, or about $10 with the audio guide. Cambodian citizens enter free.
Is the Tuol Sleng audio guide worth it?
+
Yes. It includes survivor testimonies and context for each building, and it makes a huge difference to the visit.
What are Tuol Sleng's opening hours?
+
Daily from 8 am to 5 pm.
Do I need to book S-21 in advance?
+
No. Pay at the gate.
When is Tuol Sleng least busy?
+
At 8 am, when it opens. From 9 am to 4 pm it's busy every day. See our crowd forecast.
Heading to Tuol Sleng Genocide Museum?
See how busy it is right now and the quietest hours for your date, then walk in when the line is short.
Check live crowds →Sources
How we research: every guide is written by the BeatTheCrowd team from official sources and recent traveller reports, cross-checked against each other, and dated so you know how fresh it is. Last checked 1 November 2026. Prices and rules change, so always confirm on the official site before you book.
