O'Neill Men's Thermo-X Short Sleeve Insulating Rashguard O'Neill Men's Thermo-X Short Sleeve Insulating Rashguard O'Neill Men's Thermo-X Short Sleeve Insulating Rashguard

O'Neill Men's Thermo-X Short Sleeve Insulating Rashguard

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Block out the cold in the O'Neill Men's Thermo-X Short Sleeve Insulating Rashguard. Featuring a layered fabric... Read More
SKU: 5021 Product Code: 8161302

Product Details

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    Beach Shop
    Surf Shop

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    Block out the cold in the O'Neill Men's Thermo-X Short Sleeve Insulating Rashguard. Featuring a layered fabric construction that provides insulation with low bulk and quick-drying properties, this short sleeve rashguard features a DWR coating with odor resistance to keep you fresh and comfortable, while the 4-way stretch fabric gives you maximum flexibility.


    • Nylon / Spandex.


    • Short sleeve rashguard.
    • Thermo-X Hyperdry: ?- Max insulation with minimal water absorption and a DWR coating.
    • Seamless Paddle Zones: - Flexible design which utilizes minimal seam placement for comfort.
    • UPF 50+ sun protection.
    • Odor resistance.
    • 4-way stretch fabric.
    • Boardshort connector.
    • Rash protection.
    • Low neck that won't interfere with wetsuit neck.

    Sizing & Fit

    • Tight Fit.

    Country of Origin

    • Made in China.

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  • 4.5 Review Stars (10 Reviews)

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    See all 10 customer reviews
  • 4/4/2021 It was too small. I returned it an awaiting a Medium to come in stock.

    4 Review Stars By jb

    It was returned.  Awaiting correct size.

    san francisco

    Fit: Feels too small

  • 2/16/2021 Comfortable

    5 Review Stars By Bryan

    I use this for surfing dawn patrol in Hawaii. It helps knock the chill out of the air. That's all I needed. To remove it I pull it up as far as I can and then I use the hook end of a plastic coat hanger to pull it up over my head.


    Fit: Feels true to size

  • 7/20/2020 Works

    4 Review Stars By Jack

    Helps with chilly SF East Bay temps, need to wring it out a bit before you can get it off. Otherwise fine.

    Berkeley, CA

    Fit: Feels true to size

  • 1/2/2020 I’m happy with it

    5 Review Stars By LisaR

    Nice fit and keeps me warm in the chilly public pool. Exactly what I’d hoped for.

    Newtown, CT

  • 12/24/2019 Warm, but good luck taking it off

    4 Review Stars By Zoso

    I like it, but removing it over your head when wet is extremely difficult. I wish it had a zipper in front.


    Fit: Feels true to size

  • 12/4/2019 Wearing a Sponge

    1 Review Stars By Unhappy Swimmer

    I thought this rashguard would help keep me warm when swimming in chilly water.  Boy was I wrong!  The shirt feels like it is made out of fleece, which I thought was very odd. Shouldn’t it be water repellent? Well, there is nothing water repellent about this shirt. It is a giant sponge. It soaks up water, weighs the swimmer down, and makes chilly water feel ice cold. I don’t get it. I feel like a dummy for wasting so much money on this product.

    Unhappy Swimmer
    Katy, TX

    Fit: Feels true to size

  • 9/3/2018 Good quality shirt that add some warmth

    5 Review Stars By Markus

    There are some places we go swimming where water and ambient temperature are a bit low. This shirt makes me feel comfy in these environments. The fabric seems to be of good quality and durable - but keep in mind I''m not wearing it too often, just where required. So I cannot really tell but at least it makes a durable impression.
    I bought an M size but should have bought L because M is really tight. It should be a snug fit for its purpose but keep in mind the sizes feel a bit small. So if you are torn between two sizes I recommend for you to buy the larger one.

    Parker, CO

    Fit: Feels too small

  • 3/16/2018 Thermo-X short sleeve

    4 Review Stars By adisaks

    It fits and keep me warm as I bought it for.

    Houston, Tx

    Fit: Feels true to size

  • 1/22/2018 Product is as advertized

    5 Review Stars By Philip

    I was looking for a little more insulation. I was trying to replace my instotherm body glove. The thermo x fits and wears well,but holds a lot of water when you get out of the pool.


    Fit: Feels true to size

  • 12/5/2017 Glad I bought these

    5 Review Stars By Austin

    I use them for exercising in an outdoor pool early in the morning.  My exercises consist of my uppermost body starting with my shoulders up being out of the water.   They work very well for keeping  me comfortable in the water especially when there is a breeze blowing.

    Their sizing chart is true to size.

    Austink TX

    Fit: Feels true to size

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More From O'NEILL

About This Brand


Jack O'Neill began surfing in 1952, before functional surf apparel was invented. While working for the Army Air Corps, O'Neill discovered neoprene foam in a DC-3 airplane. He then combined the neoprene carpeting with duct tape to create the first neoprene wetsuit.

Demand for O'Neill's neoprene wetsuits grew rapidly and he began a business selling the O'Neill wetsuits out of his garage. By 1980, he was a leader in the beach apparel industry with a thriving business. Since then, O'Neill™ has become a widely recognized and respected brand in the surf industry, continually creating new and innovative products. In addition to O'Neill wetsuits, they carry O'Neill boardshorts, O'Neill dresses, O'Neill hats, O'Neill rash guards, O'Neill swimsuits, O'Neill water shoes, O'Neill sandals, O'Neill life jackets and O'Neill t-shirts.

In addition to his business success, O'Neill also created a non-profit foundation for kids. O'Neill developed the O'Neill Sea Odyssey Program: a free, educational cruise that introduces kids to the microbiology of the Monterey Bay Marine Sanctuary, beginning at Jack O'Neill's doorstep.