Best Thermal Rashie: Comparing Thermal Swim Top Options

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Last Updated on September 22, 2021 by Travels with Kids

A thermal rashie is ideal when swimming in water that’s not quite cold enough for a wetsuit.  It’s also perfect when you want a more lightweight layer for swimming in the sea or an outdoor pool.  I stumbled upon these thermal rashies by accident, as I explain in more depth below.  A thermal swimsuit had not before been on my radar, until we were caught short – in our home country, no less – by the chilly winter waters of the ocean.

Hence this guide takes you through why you might need a thermal rash vest and the pros and cons of wearing one.  We also compare our recommended products for a quick, at-a-glance guide.  So stay with me to find out why thermal swimwear has been added to our family’s water sports and beachwear collection!

Click here to see our top recommended thermal rashie product – it’s the one we have personal experience of! *only available in Australia

This post may contain affiliate links, from which we would earn a small commission, at no extra cost to you. More info in my disclaimer.



Best Thermal Rashie: Comparing Thermal Swim Top Options
My son swimming on Ningaloo reef in windy conditions (hence the obscure water) in his thermal rashie

Thermal Rashie Comparison Table

Name Sizes Sleeves Features Price
Adrenalin Thermal Rashie

*only available in Australia


2XS – 2XL

Long Moisture-wicking, water repellent, flat-lock seams Click here
Finis Thermal Swim Top Youth & Adults


Long Lightweight, UV, fade, chlorine & bacteria resistant Click here
Billabong Thermal Swimsuit Top Women’s


Long Quick-drying, flat-lock seams, various colors to choose from Click here
O’Neill Thermal X Top for Men Men’s


Short Low neckline, water repellent, odor resistant Click here
O’Neill Thermal X Top for Women Women’s

S – XL

Long Odour & UV resistant, low neck, quick-drying Click here


Thermal Rashie FAQs and What to Look For


What’s a Thermal Rashie and Why do I Need a Thermal Swim Top?

Here is a parenting admission for you: I didn’t pack our wetsuits for a trip to the Ningaloo Reef several weeks ago. Oops!  Despite the fact that we were heading to the tropics, it didn’t occur to me to check the water temperature before we left.  Even though it was winter in Western Australia!

After one very brief swim on the beautiful Bundegi Beach, I thus had to head to the shops.  My initial thought was to hire wetsuits for the whole family, but doing that kind of thing hurts the hip pocket.  As an active family who enjoys water sports in the southern part of Western Australia, where we live, we already had wetsuits at home.

And there – at the shops – they were.  Thermal swimwear in Australia!  Clearly, we weren’t the only family feeling the cold.  We certainly weren’t, as it turned out.  Locals later told me that they’d never swim in August around the Ningaloo Reef!

My son really feels the cold and has sensory issues, so it’s crucial to keep him as comfortable as possible so he can participate in family activities.  While he will wear wetsuits, he does complain a lot about their rigidity.  However, he loves the thermal swim top, because of the flexibility it provides.

Speaking of Ningaloo Reef, read about this amazing site in Facts about Ningaloo Reef.

thermal swimwear

What’s so great about a Thermal Rash Vest?

Let’s ditch the sales pitch and complicated explanations about different fabrics.  Thermal swimwear, for the purposes of this post, is not a wetsuit!  If you are looking for a thermal swimsuit that is made out of wetsuit material then you should head to our post The Best Kids’ Wetsuit – Finding the Ideal Wetsuit for Your Kids.

A thermal rashie is like a sun protection rashie but is made out of thicker material for insulation and durability.  It’s not a typical wetsuit material, it’s fabric – unlike a wetsuit that is made from thick and rubbery neoprene.  A thermal swim top is aimed at people who spend a lot of time in chilly water (but not icy or freezing cold water) and would like the added protection and warmth.  It’s also good for people who find that wetsuits restrict their movements.

Advantages of a Thermal Rashie

The main advantages of a thermal mashie for swimming are:

  • Freedom of movement.
  • Greater warmth in cold water.
  • Top only.  Therefore you don’t have the feeling of being restricted that can come with a shorty wetsuit.

Disadvantages of a Thermal Rash Top

The key disadvantages of thermal swimwear for toddlers, kids, teens, and adults are:

  • As shorty wetsuits do heat your bottom and legs as well as your core, they are warmer to wear than a thermal rash vest used in Australia or elsewhere.
  • The thermal rashie is not made out of neoprene that floats.  So, when you get out of the water, it can feel quite heavy and as if it’s dragging you down.
  • The thermal rashie women’s product I have is hard to get off your head when it’s wet.  It would be better if it had a zipper-like a wetsuit, as seen on this product.  Do note, this one is NOT thermal.  However, none of the thermal ones seem to have a zip like this.

thermal swimwear

Why Would I Need a Thermal Rashie in Australia?

If you are an Aussie, you know that contrary to popular images shared around the world – Australia in fact does have some very cold oceans!  In fact, all the southern states – like Victoria, Tasmania, South Australia, and the bottom part of Western Australia – are on the Southern Ocean, and the water flows directly from Antarctica.

It’s therefore too cold to comfortably swim in these regions for more than half the year.  In fact, usually it’s only comfortable during the height of summer!  So, the short answer is yes – you may need a thermal rashie in Perth, Melbourne, Adelaide, or Hobart.  As well as many other places.

What this Thermal Swimwear is Made From

Please Note:

When you do search for a thermal swim vest or rashie, you will come across a lot of ‘neoprene’ tops, but these are still a type of wetsuit.  Neoprene is a rubbery fabric that is stretchy, buoyant, and flexible, and thus for most swimsuit producers, it is their go-to material.  It is available in various thicknesses ranging from 2mm to 6mm for summer or winter wear.  Thicker neoprene makes for a warmer wetsuit.

This is the one I have.  My son has the same brand but is wearing an adults’ XS size (he is nearly 8).  There is also a short-sleeved version.  You can read more about these Adrenalin Rash Tops in the first product listing, below.

5 of the Best Thermal Rashie Products


Whether you’re looking for a thermal rashie in Australia, the US, Europe, South America, or Asia, here are the top thermal swim vests we’ve found.

Best Thermal Rashie: Comparing Thermal Swim Top Options


Adrenalin Thermal Rash Vest

  • Long-sleeved
  • Men’s size 2XS – 2XL

This is the one that my son has in the XS size.  He’s nearly 8 years old, so the XS size is suitable for kids around that age.

An Adrenalin Thermal Rashie is a sought-after item, and these thermal rashie products are very comfortable, supple, and durable.  The ‘2P’ part of the name refers to the material used in their manufacture, which is moisture-wicking, water repellent, and has good stretch.  This breathable fabric retains less heat than a typical neoprene wetsuit top and offers the wearer protection against sun and wind.

For what they offer, I think these Adrenalin thermal rashies are great value for money.  The water repellency of the material wicks cold water away quickly, which is key as wind chill can be felt up to 25 times more when skin is wet.  These thermal swimsuits with 4-way stretch are also lined with a flexible, fleecy layer to keep kids and adults warm and offer the maximum possible sun protection (SPF 50+).

Additional practical features include the flat-lock seams that are stitched this way for added durability and comfort.  They also help to guard against rashes.  Each Adrenalin Thermal Rashie also is longer in the body than average.  This helps you to avoid the uncomfortable and unsightly ‘riding up’ of your top.


  • Breathable, moisture-wicking fabric
  • Water repellent & UV protection
  • Flat-lock stitched seams


  • Not anti-bacterial
  • Only available in Australia

Finis Thermal Swim Shirt

  • Long-sleeved
  • Youth & Adult sizes XS-XL

This Finis Thermal Swim Top is made from the brand’s own ‘bipoly’ fabric.  This is lightweight yet very strong, and also molds to the wearer’s torso while allowing complete freedom of movement.  The fabric has several important qualities that make it worth the investment.  It is UVA and UVB resistant, thus offering a good level of sun protection. It is also resistant to chlorine and fading and is anti-bacterial.

This makes it ideal for pool wear as well as swimming in the ocean and means that the smart black finish won’t fade to grey over time.  The anti-bacterial properties also fight against odor.



  • Durable yet lightweight
  • UV, chlorine & fade resistant
  • Anti-bacterial material



  • Higher price

Osprey Thermal Rashie


  • Long-sleeved
  • Women’s sizes XS-XL

If you want a thermal rashie in a women’s size, this Osprey one comes from another top outdoor brand.  It’s made from ultra-soft fabric that is thermal, comfortable, and quick-drying.  The look is good too, as it could even pass as a regular top while dry.  Like the Adrenalin rash vests, it has flat-lock stitched seams for added strength and comfort.  It can be worn beneath a wetsuit if required, thus providing added protection when the water is colder.  Such as when you’re away on vacation somewhere colder than usual.

This women’s thermal rashie also offers SPF 50+ protection and has long sleeves to keep your arms snug.  There is even a built-in board shorts connector to prevent it from riding up during wear.  Spandex also allows for a natural range of movement during swimming or water sports.



  • Quick-drying thermal material
  • Board shorts connector
  • Flat-lock seams



  • Tricky to put on or take off
  • Only available in Australia





Billabong Thermal Rashie

  • Long-sleeved
  • Women’s sizes XS-XL

This thermal rashing from Billabong is from another top outdoor brand.  It is ultra-comfy and comes in a variety of different styles and colors.

Like some of the others, this women’s thermal rashie also offers SPF 50+ protection and has long sleeves to keep your arms.



  • Quick-drying thermal material
  • Different styles and colors to choose from



  • Tricky to put on or take off

O’Neill Thermo X Top for Men

  • Short-sleeved
  • Men’s sizes XS – XXL


Being the original wetsuit brand, it’s not surprising that O’Neill has come up with the goods here too.  This men’s O’Neill Thermal Rashie is supple and lightweight, providing warmth for chilly days without too much weight.  The Skin Cancer Foundation endorse this product for the SPF 50+ protection it provides.  A nylon and spandex mix provides good stretch, and the fabric is also odor resistant and water repellent.

This one is also ideal for wearing with a wetsuit, as the ultra-low neckline won’t get in the way.  It can be worn alone or is good for layering when the ocean is even colder.



  • Odor-resistant & water repellent
  • Spandex for stretch
  • Low neckline for layering


  • Not the warmest option

O’Neill Thermo X Rashie for Women

  • Long-sleeved
  • Women’s sizes S – XL


O’Neill also makes a women’s version of the Thermo X, available in sizes small to extra large.  They supply a handy sizing chart with the listing, so you can see if the smaller sizes would fit your child.  Again the material is rapid-drying, odor-resistant, and water repellent, and offers superior UV protection of SPF 50+.  The ultraviolet protection is also Skin Cancer Foundation endorsed.

Like the men’s one, the women’s has a super low neckline so it can be layered beneath a wetsuit where required.  This stretchy, multi-purpose thermal rashie can be worn alone to ward off the chill or beneath your wetsuit for swimming and surfing in really cold water.



  • Water repellent & odor resistant
  • Quick-drying
  • Ultra-low neckline



  • Not as warm as others
thermal swimwear australia
I thought that this was a super cool photo of the thermal rashie in action!

The Verdict – Which Thermal Rashie will you Wear?

As you can see, a thermal rash vest is ideal for swimming or water sports when the ocean isn’t quite cold enough for a wetsuit. Buying a good thermal rashie for use in Australia or overseas can open up new possibilities when you want to swim during winter – or even in summer in the colder parts of the world.

A decent thermal swimsuit like this can also be layered beneath a wetsuit when the water is really chilly, and as they offer UV protection you can also save time and money on sunscreen. After owning them for only a matter of weeks, we’re already wondering what we’d do without our thermal rash vests!


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Hi! We are a multicultural family from Peru, Nicaragua & Australia. We believe adventures can be global – and local – and are one part of our sustainable lifestyle, and raising children who are global eco-citizens.