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Can you fly with a blood clot?

Written by: Russell Wallace | Travel Insurance Expert
Last updated: 24 November 2023 | Created: 11 May 2018
Can You Fly With A Blood Clot? View from plane window of the sky

Before you fly with a blood clot – understand what a blood clot is

Blood clots are vital to our bodies’ healing process – helping to stop bleeding after an injury.

In the majority of cases, the body breaks them down once the wound has healed and re-absorbs the matter. However, problems can begin when this does not happen.

A blood clot, medically known as a thrombosis, can occur in arteries and veins – and in the heart, brain, lungs, abdomen arms and legs. The real danger occurs when a clot breaks loose and travels through the bloodstream, interrupting the normal flow of blood through the body.

Sitting still for long periods – such as during long flights – can cause changes in blood circulation and can increase the risk of a clot.

Which is why the following preparations are so important when it comes to flying with a blood clot.

How soon after surgery can you fly?

This varies from patient to patient and it’s essential that you discuss this with your doctor. Particularly if you’ve previously had a clot, recently had surgery or have an existing circulatory condition.

If you’re on a blood-thinning medication, the risks are already lowered and you can be hopeful of being cleared fit to travel. Some airlines may request proof that you are fit-to-fly by asking for a Fit-to-Fly Certificate.

Once you have the ok, make sure you’ve got enough medication for the duration of your trip.

How do you minimise the risk of a blood clot?

Here are some tried and tested tips recommended by medical professionals!

Before flying

  • Prepare your hand luggage: Have you got your medicine? Be sure to take any prescribed medicine before you fly. And what about flight socks and a tennis ball? (see below)
  • Choose your seat carefully: Consider reserving an aisle seat or pay that little extra for a seat with more leg room
  • Tell the airline: Let your carrier know about your condition and that you will need to move around regularly while airborne as a result. Do so in advance, but also remind the crew before you board
  • Choose the right clothes: That means loose-fitting items to ensure your blood flow is not restricted. This includes your choice of footwear!

In the air

  • Wear flight socks: Also known as compression stockings, they reduce the risk of DVT. But be sure to get the right size, weight and fit for you. And try not to cross your legs!
  • Exercise: Yes, even while you’re in flight! It is unwise to remain seated for the duration of your flight and taking a toilet break is not enough… Walk around at least once an hour or stand for periods of time. Also, make the most of the extra leg room you paid for and do stretching exercises. These stretches can include flexing the calf muscles, stretching thigh muscles and curling and stretching your toes.
  • Drink lots of fluids: This does not include alcohol, which can dehydrate and increases the risk of your blood thickening. There will be time for that glass of wine or beer at your destination! Instead, drink plenty of water instead to keep hydrated.
  • Massage your muscles: Take a tennis ball to massage your leg muscles by pushing it into your thigh and rolling it up and down your leg. Doing so will help promote circulation.

Who is susceptible to blood clots?

Blood clots can cause problems for anyone, but certain people are particularly at risk.

Key factors include…


If there is a history of strokes in your family or any close relatives, think about checking with your doctor if your genetics put you at any greater risk.

Surgery patients

Those who’ve had surgery on the legs or pelvic area, and required bed rest are at a greater risk. The reason surgery in general can cause a blood clot, is that large blood vessels can be damaged during surgery.


In taking tobacco leads to slower blood flow through the body and a thickening of the blood.

Pregnant women

Inevitably, being pregnant places extra pressure on the veins in the pelvis and legs, increasing the clot risk. This remains for around six weeks after birth.

People with cancer

Certain cancers can cause tissue damage that triggers clotting. Some types of chemotherapy also make clotting more likely.

Patients taking certain medicines

The main risk if from any medicine containing sex hormones, which includes the contraceptive pill and Hormone Replacement Therapy (HRT).

Being overweight

As with pregnancy, carrying increased weight places pressure on the veins in the legs and pelvis, thus increasing the risk of clotting.

People living with Inflammatory Bowel Disease

For example those who have Crohn’s Disease and Ulcerative Colitis.


This particularly applies to endurance athletes, such as triathletes and marathon runners, who get clots more easily due to injury and dehydration.

What type of blood clots are there?

    • Arterial clots: They form in the arteries, the large vessels that pump blood away from the heart. Symptoms can present immediately and arterial clots are most common in your legs, feet, heart and brain.
    • Venous clots: They form in the veins, usually over time. As a result of this, the symptoms can take time to be felt and are often mistaken for something else. There are three different venous clots – Deep Vein Thrombosis (DVT), Superficial Venous Thrombosis (SVT) and a Pulmonary Embolism (PE).
    • SVT: These form in a vein near the skin surface and can be painful, but generally do not break loose, so are less dangerous.
    • DVT: A blood clot that forms deep in your body, often in the leg, pelvis or thigh.
    • PE: This is a DVT that breaks free and travels through your body to the lungs, where it sticks. A pulmonary embolism can be life-threatening and urgent medical help should be sought.