Conditions
Seasickness: prevention and medicine before you sail
Seasickness is easier to prevent than to stop: the CDC says motion-sickness medicine works best when taken before you set out, not once you already feel sick. If you are taking the ferry to Culebra or Vieques, a catamaran trip or a cruise, our doctor can see you by video and, if appropriate, prescribe and send your prescription to your pharmacy. You must be in Puerto Rico during the visit.
Is it an emergency? Call 911.
Is this an emergency?
This is not an emergency service. Call 911 or go to the nearest emergency room if you have:
- Vomiting that won't stop, or no fluids kept down for hours
- Dizziness with chest pain, shortness of breath or palpitations
- Weakness on one side, a drooping face, trouble speaking or vision loss (call 911)
- A sudden severe headache, or a head injury on board
- Confusion or extreme drowsiness after a motion-sickness medicine
Help lines
At a glance
Seasickness
Common symptoms
- A queasy stomach and nausea
- Vomiting
- Cold sweats
- Dizziness
- Drowsiness or tiredness
- Other names
- Motion sickness · Ferry seasickness
- Treatment
- Non-medicine measures and, if appropriate, a motion-sickness medicine taken before the trip
- Possible complication
- Dehydration from vomiting
On this page(10)
What is seasickness?
Seasickness is a form of motion sickness. It happens when what your inner ear feels doesn't match what your eyes see: the boat is moving, but you are looking at something that seems still, like your phone or a cabin wall.
In Puerto Rico it hits a lot of people on the ferries from Ceiba to Culebra and Vieques, on day-trip catamarans and on cruises calling at San Juan. Dizziness on dry land, with no boat involved, is something else: see a doctor. And if you have nausea with no motion involved, see that guide.
How we treat seasickness by video
You see Dr. Diana Nieves Castro, a Puerto Rico-licensed general practice physician with several years of emergency-department experience, in English or Spanish. The best time to book is the day before your boat trip, so you have time to pick up the medicine.
The doctor asks how long the trip is, whether you have been seasick before, what medicines you take, and whether you have glaucoma, trouble urinating or could be pregnant, because those change what is safe for you. If appropriate, the doctor prescribes and we send your prescription to your pharmacy. We do not prescribe controlled substances.
We see tourists, cruise passengers and residents; see our care for tourists and visitors. You must be physically in Puerto Rico during the visit: we can't see you once your ship has left the island. If the patient is under 21, a parent or legal guardian stays on camera for the whole visit and shows photo ID.
Your doctor
Dr. Diana Nieves Castro, MD
General practice physician
Several years of emergency-department experience.
Founding Executive Director of The Health Initiative.
Your visit in 3 steps
Request a visit online 24/7 — we confirm your time by email or text.
Request your visit.
Book a visit, choose "Doctor visit" and pay by card. The day before your trip is ideal.
See the doctor.
We send you a secure video link. It works on your phone, tablet or computer.
Get your plan.
If appropriate, the doctor prescribes and we send your prescription to a pharmacy near you on the island.
What the visit costs
A doctor visit costs US$79, the same price for every age, with no membership. Your card is charged when you request the visit, and you get a full refund if the visit can't take place. We do not bill insurance; on request we give you an itemized receipt (superbill). See all prices.
Motion sickness symptoms
According to the CDC and MedlinePlus, motion sickness can start suddenly with:
- A queasy stomach and nausea
- Vomiting
- Cold sweats
- Dizziness
- Drowsiness or tiredness
Seasickness medicine: take it before you sail
The CDC says motion-sickness medicine works best when taken before you are exposed to motion. The CDC's figures for when each one starts working:
- Scopolamine patch: starts working 6 to 8 hours after you put it on and lasts up to 72 hours. Useful for long trips such as a cruise. Not used with glaucoma or if you have trouble urinating, and avoided in children.
- Meclizine: starts in about 2 hours and lasts 8 to 24 hours.
- Dimenhydrinate: starts in about 2 hours and lasts about 8 hours.
All of them can cause drowsiness and a dry mouth, so don't drive after taking one. The doctor decides what is appropriate for you; we never promise a specific medicine. If you get a prescription, pick it up before you head to the dock: see 24-hour pharmacies in Puerto Rico, because the pharmacy counter isn't always open when the store is.
What to do on board without medicine
According to the CDC, getting used to the motion works best of all, better than medicine. Also:
- Sit where the boat moves least and look at the horizon.
- Don't read or look at your phone during the trip.
- If you can, lie on your back and keep your head still.
- Breathe slowly and steadily.
Seasickness in children
The CDC advises starting with the non-medicine measures and avoiding scopolamine patches in children, because they can cause confusion or hallucinations. Ask before giving a child any motion-sickness medicine; we see children of all ages with their parent or legal guardian on camera.
When to go to the ER
Seasickness fades soon after you are back on land. If vomiting won't stop and you can't keep fluids down for hours, you can get dehydrated: read about dehydration.
Call 911 if dizziness comes with chest pain, shortness of breath, palpitations, weakness on one side, a drooping face, trouble speaking or vision loss. On a cruise, tell the ship's medical center first; see the cruise passenger guide.
How we care for you
We evaluate, diagnose and treat; if needed, we give you a lab order for a lab near you.
We see adults and children of all ages. Patients under 21: a parent with patria potestad (parental authority) or a legal guardian is on camera for the whole visit and shows photo ID.
Real-time video visit. We send you a secure video link. It works on your phone, tablet or computer.
If appropriate, the doctor prescribes and we send your prescription to your pharmacy. We do not prescribe controlled substances.
You must be physically in Puerto Rico during the visit (visitors, tourists and cruise passengers are welcome).
In an emergency, call 911.
Frequently asked questions
How long before the ferry should I take seasickness medicine?
Can I get a seasickness patch prescribed by video?
What should I do if I get seasick on the Culebra or Vieques ferry?
Can children use a seasickness patch?
About this page
Author: The Health Initiative
Medical care provided by Dr. Diana Nieves Castro, MD (PR license 24027)
Disclosure: Founding Executive Director of The Health Initiative
Published: 2026-10-02 · Updated: 2026-10-02
Sources (3)
- Motion Sickness, CDC Yellow Book (CDC) (opens in a new tab) (accessed 2026-10-02)
- Motion Sickness (MedlinePlus, NIH) (opens in a new tab) (accessed 2026-10-02)
- Puerto Rico Ferry: Ceiba–Culebra and Ceiba–Vieques routes (opens in a new tab) (accessed 2026-10-02)