Short answer: Deep vein thrombosis (DVT) is a blood clot in a deep vein, usually in the leg. Surgery and long periods of sitting, such as on a long-haul flight, both raise the risk (healthdirect (opens official site)). UK guidance treats major surgery in the previous 4 weeks as a high-risk factor for travel-related DVT (NICE CKS (opens official site)). If you’ve had surgery overseas, ask your surgeon about your personal clot risk before you book the flight home.
Risks and limitations to understand first
| Point | What it means |
|---|---|
| A clot can travel to the lungs | A pulmonary embolism can be a medical emergency and can be fatal (ASAPS (opens official site)). |
| Longer flights, more risk | Risk increases after 4 hours of travel and rises with duration (NICE CKS (opens official site)). Flights home from Thailand or Türkiye are much longer than that. |
| Risk persists after surgery | Clot risk is highest in the first 3 months after surgery (NHLBI (opens official site)). |
| Prevention reduces risk but can’t remove it | Even with every precaution, clots can still happen. |
Who’s at higher risk?
healthdirect lists factors that increase DVT risk (healthdirect (opens official site)):
- being in hospital for surgery or a major illness
- sitting still for a long time, such as on a long-haul flight
- an injury such as a fracture
- cancer or heart failure
- oestrogen-containing treatments, such as the contraceptive pill or hormone replacement therapy
- pregnancy
- a genetic tendency to clot
- being overweight
- smoking
ASAPS says procedures that limit your mobility afterwards, such as tummy tucks, body lifts and large-volume liposuction, add to the risk (ASAPS (opens official site)). Joint replacements also need individual advice. NICE notes there’s no consensus on travel after hip or knee replacement, and suggests asking a specialist (NICE CKS (opens official site)). See our guides to tummy tucks, liposuction, body lifts, hip replacement and knee replacement.
Warning signs
- pain, swelling, warmth or redness in one leg, usually the calf: see a doctor the same day
- chest pain, sudden shortness of breath or coughing up blood: call 000
The reviewer should confirm this symptom list. If you’re still overseas, use the local emergency number. Our complications guide has more detail.
Reducing the risk
On long journeys, healthdirect recommends (healthdirect (opens official site)):
- Get up and walk around every 1 to 2 hours.
- Do calf stretches or heel lifts in your seat.
- Drink plenty of water.
- Avoid alcohol and caffeine, which can add to dehydration.
- Wear compression stockings if you have other DVT risk factors.
A Cochrane review of airline passengers found that compression stockings reduced symptomless DVT on flights longer than five hours (Cochrane via PMC (opens official site)). Make sure they fit properly.
Some people at high risk may be offered medicine to prevent clots. That’s an individual decision for your doctor (NICE CKS (opens official site)). Don’t start anything without advice.
Plan the timing. Delaying travel may be appropriate after surgery (NICE CKS (opens official site)). See how long after surgery you can fly for what different bodies advise, and the airline clearance rules.
Long flights home from popular destinations
- From Bali: see medical tourism in Bali and Seminyak, Canggu and Denpasar.
- From Thailand: see Thailand, Bangkok and Phuket.
- From Türkiye: see Turkey, Istanbul and Antalya. The trip home takes around 20 hours or more.
Frequently asked questions
Does flying after surgery cause DVT?
Both surgery and long flights increase the risk of DVT, and combining them adds to it. Most people don’t develop a clot, but the risk is real and can be serious.
How long after surgery is clot risk highest?
NHLBI says it’s highest in the first 3 months after surgery. NICE treats major surgery in the previous 4 weeks as a high-risk factor for travel-related DVT.
Do compression stockings help on long flights?
A Cochrane review found that they reduced symptomless DVT on flights longer than five hours. healthdirect recommends them if you have other risk factors.
What are the symptoms of DVT after a flight?
Pain, swelling, warmth or redness in one leg. Chest pain or sudden breathlessness can mean a clot in the lungs, which is an emergency.
Should I take something to prevent clots before flying?
Only if your doctor advises it. Medicine to prevent clots is considered individually for people at high risk.
Sources
All accessed 22 October 2026.
- healthdirect, Deep vein thrombosis: https://www.healthdirect.gov.au/deep-vein-thrombosis
- NICE CKS, DVT prevention for travellers: https://cks.nice.org.uk/topics/dvt-prevention-for-travellers/management/dvt-prevention-for-travellers/
- NHLBI, Preventing blood clots: https://www.nhlbi.nih.gov/health/venous-thromboembolism/preventing-blood-clots
- ASAPS, Thinking of having cosmetic surgery overseas? Know your risks: https://aestheticplasticsurgeons.org.au/resources/thinking-of-having-cosmetic-surgery-overseas-know-your-risks-2/
- Cochrane review, Compression stockings for preventing deep vein thrombosis in airline passengers: https://pmc.ncbi.nlm.nih.gov/articles/PMC8092568/
Disclaimer: The information on medicaltourism.com.au is general in nature. It isn’t medical advice and doesn’t take your personal circumstances into account. Talk to a registered health practitioner about your own risk. See our editorial policy, medical disclaimer and how we make money.