The Best Compression Socks for Flying

While compression socks benefit virtually anyone on a long flight, certain groups face elevated risk and should consider them essential rather than optional. Here are the key risk factors that make compression socks particularly important:

• • Flights over 4 hours: The risk of DVT begins to increase meaningfully after four hours of immobility. Transatlantic, transpacific, and any route involving a long layover qualifies. If your total travel time including connections exceeds four hours, treat it the same as a single long flight.
• • Travelers over 40: Age is one of the strongest independent risk factors for DVT. The risk roughly doubles for each decade of life after 40, making compression socks an increasingly smart precaution as you get older.
• • Pregnant travelers: Pregnancy significantly increases the risk of blood clots due to hormonal changes that make blood more likely to clot and the pressure of the uterus on pelvic veins. Many obstetricians recommend compression socks for any pregnant woman flying, even on shorter routes.
• • History of blood clots or varicose veins: Anyone who has had a previous DVT, pulmonary embolism, or who lives with varicose veins has an elevated baseline risk. Compression socks are considered standard medical advice for this group during air travel.
• • Frequent flyers: Cumulative exposure to long flights compounds risk over time. Business travelers, digital nomads, and anyone who flies regularly should make compression socks part of their standard packing list.
• • Window seat passengers: Studies have shown that window seat passengers are less likely to get up and move during a flight, leading to longer periods of uninterrupted immobility. If you prefer the window seat, compression socks help compensate for that reduced movement.
• • Travelers taking hormonal contraceptives or HRT: Estrogen-containing medications increase clotting risk, and combining them with the immobility of long flights elevates that risk further.

Compression Levels Explained

Compression is measured in millimeters of mercury (mmHg), the same unit used for blood pressure. The number refers to the amount of pressure the sock applies at the ankle, which is always the point of maximum compression. Here is what each level means and who it is for:

• • 8-15 mmHg (light support): Provides minimal compression, roughly equivalent to a snug athletic sock. Suitable for daily wear to reduce mild leg fatigue but generally insufficient for the circulatory challenges of air travel. Not recommended as your primary flight sock.
• • 15-20 mmHg (moderate compression): The most popular level for casual travelers. Provides noticeable support that reduces swelling and fatigue without feeling overly tight. A good choice for flights under six hours, travelers new to compression socks, or anyone who finds higher compression uncomfortable. This is the level used by CHARMKING, FuelMeFoot, and Sockwell.
• • 20-30 mmHg (firm, medical-grade compression): The level recommended by most vascular specialists for long-haul flights. Delivers significant circulatory support that meaningfully reduces DVT risk. Can feel tight when first putting them on, but most people adjust within minutes. This is the level used by Physix Gear, SB SOX, and CEP. If you fly routes over six hours regularly, this is the compression level you want.
• • 30-40 mmHg (extra firm, prescription strength): Reserved for people with diagnosed venous conditions, post-surgical recovery, or severe edema. Should only be worn under medical supervision. Too much compression for healthy travelers and can actually restrict blood flow if worn without medical necessity.

Material Matters: Merino Wool vs. Synthetic vs. Cotton Blend

The fabric your compression socks are made from affects comfort, temperature regulation, odor resistance, and longevity. Here is how the main material categories compare:

• • Merino wool blend (Sockwell): The premium option. Merino wool naturally regulates temperature, keeping feet warm in cold cabins without overheating. It is naturally antimicrobial, meaning it resists odor far better than synthetics over multi-day wear. The downside is cost and a slightly longer drying time after washing. Best for travelers who value natural fibers and plan to wear socks on consecutive travel days.
• • Synthetic blends (nylon, polyester, spandex): The most common material for compression socks and what the majority of options on this list use. Synthetics are durable, wick moisture effectively, and dry quickly. They maintain compression well over time and are easy to care for. The trade-off is that synthetics develop odor faster than merino wool and do not regulate temperature as naturally. Best for most travelers who want a reliable, low-maintenance sock.
• • Cotton blend: While comfortable against the skin, cotton absorbs and retains moisture rather than wicking it away. This makes cotton blend compression socks a poor choice for long flights where your feet will be enclosed in shoes for extended periods. Cotton also loses its shape faster, meaning the compression degrades sooner. We generally do not recommend cotton blend compression socks for air travel.

How to Measure for Compression Socks

Proper sizing is critical. Compression socks that are too loose will not provide therapeutic benefit, while socks that are too tight can restrict circulation and cause discomfort. Follow these steps:

• • Measure in the morning before any swelling occurs, as your calves will be at their smallest
• • Calf circumference: Wrap a flexible tape measure around the widest part of your calf, typically about halfway between your knee and ankle
• • Ankle circumference: Measure just above the ankle bone at the narrowest point
• • Shoe size: Most brands also factor in your regular shoe size
• • Compare all three measurements to the specific brand's size chart, as sizing varies significantly between manufacturers
• • Between sizes: For 15-20 mmHg socks, size down for a snugger fit. For 20-30 mmHg socks, size up for comfort since the compression is already firm
• • If one calf is noticeably larger than the other, size based on the larger measurement

Length: Knee-High vs. Ankle

For air travel, knee-high compression socks are the only correct choice. During flights, blood pools in the entire lower leg between the ankle and the knee. Knee-high socks apply graduated pressure along this full area, supporting the calf muscles in pumping blood upward. Ankle-length compression socks address only the foot and completely miss the calf region, which is where deep vein thrombosis most commonly originates. Every medical guideline for DVT prevention during air travel specifies knee-high compression hosiery. Ankle compression socks have their uses in athletics and daily comfort, but they are not effective for the specific circulatory challenges of flying.

Compression socks are safe for the vast majority of healthy adults, but there are situations where you should consult a medical professional before wearing them:

• • You have peripheral artery disease (PAD) or other arterial circulation issues
• • You have severe peripheral neuropathy that reduces sensation in your legs
• • You have a skin infection, open wound, or dermatitis on your lower legs
• • You experience numbness, tingling, or increased pain while wearing compression socks
• • You have congestive heart failure or other conditions that cause fluid retention
• • You are unsure whether your condition is compatible with compression therapy

If you have a history of DVT or blood clotting disorders, your doctor may recommend a specific compression level or prescription-grade socks rather than over-the-counter options. Always follow your physician's guidance over general recommendations.