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Scuba Wetsuit Thickness Guide: Best Thickness for Every Temp

Everyone knows what a wetsuit is or at least what it’s supposed to look like. Maybe if you are even more knowledgeable, you will even know how much a wetsuit costs. A wetsuit is a full-body suit made of neoprene and its main job is to keep swimmers or divers insulated as they dive deeper into the water. Being submerged in the water means that divers and swimmers are often exposed to some very low temperatures, which could trigger several health issues such as hypothermia or delirium.  

Though many people know about wetsuits, something that a lot of people don’t know is that they come in different levels of thickness that are perfect for different temperatures. Here is a rundown of the best thickness for every temperature. 


7mm- 5 degrees 

7mm wetsuits are the thickest available wetsuits and are perfect for when the water starts to get extremely cold. This thickness is the top pick for divers who want to explore the water when there is snow or rainfall outside. This wetsuit is also useful against temperatures that are close to freezing, as 7mm is thick enough to create a large barrier between yourself and the ice water.  A lot of people are hesitant to wear wetsuits of this thickness as they believe that it will limit flexibility and movement, but this really isn’t the case. Neoprene is a very flexible material, which means even when it is thick, you have plenty of movement.  

Wetsuits of this thickness are even perfect for when you plan on going on deep dives and falls under the recommended gear that you use when doing so, along with a scuba diving full face mask. This is because the water actually feels much colder the deeper down you go, so if you plan on going quite deep, you will want a protective layer.  


6mm- 6 degrees 

Though this wetsuit thickness isn’t the best for when the water is at freezing temperatures, it is still a great thickness for combatting the colder months. Professional divers and swimmers usually switch to their 6mm wetsuits in winter,  so between the months of November and February.  Though these wetsuits are a lot thicker, special measures are often put into place to make sure that they dry out quicker. There is nothing worse than jumping out of the water in the middle of winter then having to wait for a thick layer of wet material to dry, so most companies that sell wetsuits try to combat this.  


5.5mm 9 degrees 

Once the weather starts to drop at the beginning of winter and the end of fall, you will want to upgrade your standard wetsuit thickness to 5.5mm. This is perfect for when the water starts to get a little cooler and is even worn throughout summer for people who aren’t a huge fan of the cold.  People who are less susceptible to cold also favor this thickness for winter times, as they feel as though there is less restriction with this thickness of the material. This thickness is also favored among surfers during the colder months due to the fact that the material is fast drying, meaning they can stay warm whether they are in or out of the pool.  


5mm-11 degrees 

This is the thinnest recommended wetsuit once the water starts to get colder in winter. This is helpful not only when you’re in the water but also when you are out on the beach surrounded by a cold breeze. Though this thickness is usually enough to keep you warm in the colder months, people recommend that you wear an insulating underlayer as the temperature of the water can be unpredictable as it gets colder and you could find yourself very cold the deeper you go. 


4.5mm- 12 degrees 

This thickness is perfect for the fall weather where temperatures really start to plummet and the air gets colder. At this point of the year, the day can start off quite warm and then start to get colder as the day goes on and clouds cover the sun. Again, a lot of divers and surfers recommend that people wear a layer of insulation underneath the actual wetsuit, as the weather can fluctuate throughout the day and make the water warmer or colder, so it is best to be safe rather than sorry.  


4mm- 14.5 

This thickness is usually what people wear throughout the year and it offers slightly more warmth than a 3mm thickness wetsuit. A lot of people start to wear this wetsuit towards the end of summer when the evenings start to get a little cooler. This thickness will keep you well insulated but it is not ideal to use it in winter or autumn, as the weather will be much too cold for that. However, if you are someone that isn’t in a position where you can purchase another wetsuit, this wetsuit can be matched with an insulated undershirt that will improve how much heat you maintain. 


3mm- 16.5 degrees  

Due to the fact that most watersports take place during the summer, the 3mm wetsuit is probably the wetsuit that you are most familiar with.  This wetsuit is one of the most commonly used wetsuits all year round and is a go-to in the warmer months. This swimsuit is rather thin and so is perfect for the hottest months of the year, where the water is warm and the last thing that you want is to feel constrained by a thick material. People also use this wetsuit thickness as they go into fall, with the support of a couple of insulating layers underneath.  


Which thickness is right for you? 

Really it is up to the user to decide which thickness meets their needs. Every human is different and there are a number of factors that come into play when deciding which thickness to go for. For example, people with a higher body fat percentage may want to go for a thinner wetsuit, as their body is already well insulated. Whereas someone with a lower body fat percentage may want to go with a thicker swimsuit all year round as they may find it harder to maintain heat when underwater. It is also important to remember that swimming and diving are really hard workouts that may lead you to sweat more anyway, and for this reason, a lot of people choose to go with thinner wetsuits so that they don’t feel as overwhelmed with heat in the water.