If you need PEP on Koh Phangan or Koh Tao, you have two good options: get seen by a local clinic, or take a boat to Koh Samui. Either way, PEP must be started within 72 hours, and the sooner the better, so the right choice is usually whichever gets you in front of a doctor fastest.
This guide is for everyday island life: dive instructors, residents, digital nomads and long-stay travellers. If your question is about a party weekend, our page on PEP after the Full Moon Party covers that situation.
Can you get PEP and STD tests on the smaller islands?
Yes. Koh Phangan and Koh Tao both have private clinics, and some advertise HIV PEP, PrEP and STD testing for visitors. Koh Phangan also has a public hospital. A local clinic is often the fastest route, especially at night.
What varies is stock, lab access and follow-up. Smaller clinics may not keep every medicine or test on site, and samples for some tests are often sent to a lab on another island or the mainland. That can mean waiting longer for results.
Questions to ask a local clinic first
- Do you have PEP medicines in stock right now, for a full 28 days?
- Can you do a baseline HIV test today?
- Which STD tests are done on site, and which go to an outside lab?
- How will I get my results and follow-up plan?
Local clinic or boat to Koh Samui?
The best choice depends on the time since exposure, the boat schedule and how you feel. A doctor will assess your situation either way, but it helps to know the trade-offs before you message anyone.
Getting help locally vs travelling to Koh Samui
| Option | Pros | Cons | Typical time to be seen | Choose it when |
|---|---|---|---|---|
| Local clinic on Phangan or Tao | No boat; quick; good if unwell | Stock and lab tests can be limited | Often within an hour or two | Time is short, boats have stopped, or the sea is rough |
| Boat to Koh Samui | Wider choice of clinics and labs; easy flights home | Boat plus taxi time; weather delays | Usually half a day from Tao, less from Phangan | You are still well inside 72 hours and boats are running |
| Start locally, follow up on Samui | Fast start plus a longer-term care base | Records need to travel with you | Same day to start | You want PEP now and regular care later |
Never let a boat trip push you close to the 72-hour limit. If in doubt, start locally and sort out follow-up afterwards. Our step-by-step plan for the first 72 hours after a condom breaks explains why every hour counts.
Boat routes to Koh Samui (approximate)
Crossings between the islands are frequent in daytime, but schedules change with the season. Always check current timetables with the operator or your pier before you rely on them.
Approximate boat options to Samui (check current timetables)
| Route | Boat type | Approximate crossing | Good to know |
|---|---|---|---|
| Koh Phangan to Koh Samui | High-speed catamaran | About 20–45 minutes | Several daytime sailings from Thong Sala |
| Koh Phangan to Koh Samui | Standard ferry | About 45–60 minutes | Slower but often cheaper |
| Koh Tao to Koh Samui | High-speed catamaran | About 1.5–2.5 hours | Usually stops at Koh Phangan on the way |
| Koh Tao to Koh Samui | Slower ferry | About 2.5–3.5 hours | Fewer sailings; check arrival pier |
Most scheduled boats run during the day, with little or nothing late at night. From around October to December, the Gulf's rainy season can bring rough seas and cancelled sailings. If the weather turns, a local clinic is usually the safer choice.
Everyday island life: divers, residents and long-stay travellers
People who live on the islands have slightly different needs from short-stay visitors. You may need PEP once, but ongoing testing and prevention matter just as much.
If you dive or teach diving
Tell the doctor if you are planning to dive while taking PEP. Some people feel tired or nauseous in the first days, which could matter underwater. The doctor can help you plan dives around your course. Our guide to common PEP side effects and how to manage them explains what to expect.
If you live on the island
On a small island, privacy can feel harder. You can ask any clinic how records are stored and who can see them. Some residents travel to Samui for routine checks for extra distance from daily life.
If you have repeated risks, ask about PrEP. Our explainer on how PEP compares with PrEP and condoms sets out the difference.
STD testing on Koh Phangan and Koh Tao
For STD tests, timing matters more than location. Most infections need time before a test can find them, so there is rarely a reason to rush onto a boat the next morning for STD testing alone.
- Chlamydia and gonorrhoea: reliable from about two weeks after sex.
- Syphilis and HIV: blood tests need several weeks, with a final check around three months.
- Symptoms: if you have discharge, pain or a sore, see a doctor sooner.
If you want to compare what tests cost, see our guide to typical STD test prices on Koh Samui. UK travel health advice for Thailand also notes that drug-resistant gonorrhoea has been reported in travellers, which is one reason to test properly rather than self-treat.
What to bring to your appointment
Whichever island you are on, a little preparation saves time.
PEP and testing appointment checklist
| Item | Why it helps | Tip |
|---|---|---|
| Passport or ID | Clinics usually register patients | A photo on your phone can help if it is at the dive shop |
| Time of the exposure | Decides whether PEP is still possible | Write it down as soon as you can |
| List of your medicines | The doctor checks for interactions | Include supplements and gym products |
| Any earlier test results | Avoids repeating tests | Screenshots are fine |
| Phone with charge | For results and follow-up messages | Bring a power bank on the boat |
Getting PEP and follow-up care on Koh Samui
Koh Samui is the main medical hub for the three islands, which makes it a practical base for longer-term care. Our HIV PEP service on Koh Samui can start PEP, and confidential HIV and STI testing covers routine checks.
Started PEP on another island?
That is fine. Bring your medicines and any paperwork, and a doctor can help with the rest of the course. Follow-up support after PEP helps with questions during the 28 days, and the guide to HIV testing after PEP explains the test schedule. If cost is a worry, message us for our current price.
Frequently asked questions
Can I get PEP on Koh Phangan?
Yes, some private clinics on Koh Phangan offer PEP. Ask whether they have a full 28-day supply in stock before you go. If boats are running and you have plenty of time, Samui is another option.
Is there a sexual health clinic on Koh Tao?
Koh Tao has private clinics, and some offer STD testing and PrEP. Some samples may go to an outside lab, so results can take longer.
How long is the boat from Koh Tao to Koh Samui?
Roughly 1.5–2.5 hours on a high-speed boat and longer on slower ferries. Check current timetables, as weather changes schedules.
Can I start PEP on one island and continue on another?
Usually, yes. Keep your medicines and records together, and tell the new doctor exactly when you started.
Should I wait until I get back to Samui for an STD test?
Often that is fine, because most STD tests need about two weeks to be reliable. If you have symptoms, see a doctor sooner.
Talk to a doctor before you catch the boat
Whether you are on Koh Phangan, Koh Tao or already on Samui, the most useful first step is a quick message. A doctor can check your timing and help you decide between a local clinic and the boat. PEP must be started within 72 hours, and the sooner the better. You can message a doctor privately on WhatsApp for calm, confidential advice.