Wetsuit thickness guide: what to wear for every water temperature

What the numbers mean

Wetsuit thickness is measured in millimetres of neoprene and usually written as two or three numbers, such as 3/2, 4/3 or 5/4/3. The first number is the thickness of the neoprene around the torso, where warmth matters most. The second number is the thickness in the arms and legs, where thinner neoprene gives more flexibility for paddling and moving. A third number, when present, usually refers to the thickness in specific areas such as the arms.

So a 4/3 wetsuit has 4mm neoprene on the body and 3mm on the arms and legs. Thicker neoprene keeps you warmer but is less flexible and heavier. The right wetsuit is the thinnest one that keeps you comfortably warm for a full session in the conditions you expect.

Wetsuit styles

Full suits cover the whole body from neck to ankles and wrists and are the most common type for surfing in cool and cold water. Spring suits, or shorties, have short arms and short legs, and are used in mild water. Long-sleeved spring suits and short-sleeved full suits are in-between options. In warm water, many surfers simply wear boardshorts or a swimsuit with a rash vest or neoprene top for sun and wind protection.

Entry systems also vary. Back-zip suits are easy to put on and take off, while chest-zip and zipless suits usually seal better against water entering at the neck and offer more flexibility, which is why they are popular for cold water.

Choosing by water temperature

Water temperature is the main factor in choosing a wetsuit thickness. The table below is a broad guide, but remember that it is approximate. Air temperature, wind, sunshine and how long you plan to stay in the water all make a difference. So does your own tolerance to cold: some people feel the cold more than others, and beginners, who spend more time sitting and waiting or getting wet in the white water, often feel colder than experienced surfers who are paddling constantly.

If you are between two options, choose the warmer one, especially for longer sessions, windy days or if you tend to feel the cold. Being cold reduces stamina, slows reactions and makes surfing less enjoyable and less safe.

Boots, gloves and hoods

In cold water, the extremities lose heat fastest. Neoprene boots are commonly worn when the water drops below the mid-teens Celsius, and they also protect your feet from rocks and reef. Gloves are usually added when the water falls to around ten degrees or below, though some surfers wear them earlier. Hoods, either separate or built into the wetsuit, make a big difference to comfort in very cold water and help prevent ear problems caused by repeated exposure to cold water and wind.

Boots, gloves and hoods come in different thicknesses, typically from 3mm to 7mm. Thicker gloves are warmer but make paddling harder, so many surfers choose the thinnest gloves that keep their hands functional.

Fit matters as much as thickness

A wetsuit keeps you warm by trapping a thin layer of water against your skin, which your body warms. If the suit is too loose, cold water flushes in and out, and you lose heat quickly. If it is too tight, it restricts movement and breathing. A good wetsuit should feel snug everywhere, without gaps at the lower back, armpits or knees, and with seals at the wrists, ankles and neck that are close-fitting but comfortable.

When renting a wetsuit at a surf school, ask to try a couple of sizes. When buying, try different brands, as sizing varies, and move around to check that you can raise your arms and crouch comfortably.

What to pack for popular surf destinations

For tropical destinations such as Bali, Sri Lanka, Costa Rica, the Philippines and the Maldives, a rash vest or a thin neoprene top is usually enough, mainly for sun protection. For the Canary Islands and Morocco in winter, a 3/2 full suit is common. For Portugal, Spain and France, a 3/2 works in summer and early autumn, and a 4/3 for much of the rest of the year, with a 5/4 and boots in the north in winter.

For Ireland and the UK, a 4/3 with boots is common in summer and a 5/4 or 6/5 with boots, gloves and a hood in winter. California varies from a spring suit or 3/2 in late summer in the south to a 4/3 or 5/4 in the north year-round. Chile's Humboldt Current keeps the water cold, so a 4/3 with boots is standard.

Caring for your wetsuit

A well-cared-for wetsuit lasts longer and stays warmer. Rinse it in fresh water after every session to remove salt and sand, and dry it inside out in the shade, away from direct sunlight, which degrades neoprene. Avoid hanging it by the shoulders on a thin hanger when wet, as the weight can stretch it; folding it over a thick hanger at the waist is better. Do not leave it in a hot car, and avoid washing machines and harsh detergents. Small tears can be repaired with neoprene glue before they grow.

Rent or buy?

If you are taking lessons, surf schools almost always include a wetsuit, and renting is the easiest option for a first trip. Once you surf regularly, a wetsuit that fits you well is one of the best investments you can make for comfort and progress. If you surf in different climates, many surfers end up with two suits: a 3/2 for warmer months and a 4/3 or 5/4 for colder ones.