Sharkskin Thermal Flex Socks (Unisex)

Cold feet can cut a snorkel short, and Sharkskin Thermal Flex Socks are a thin warm layer for that problem. New for 2026, they slip on under full foot fins or go barefoot style on a paddleboard or surfboard. They come in Black, Charcoal, Orange or Pink.

How the Socks Work

The socks use the same Hydrophobic Nanotech Compression fabric as the rest of the Thermal Flex range, with Far Infrared (FIR) technology woven in to help keep heat close to your feet. Since there is no neoprene, they stay slim and don't bring the bulk or buoyancy a neoprene sock would. The fabric also repels water and keeps absorption low, so the socks stay lighter and less clammy when you get out.

Many swimmers and paddlers wear them on their own, and snorkelers can use them to make fin pockets more comfortable while adding warmth. They also carry UPF50+ sun protection for the tops of your feet on long surface swims.

Sizing

These unisex socks come in three paired sizes, XSM-SML, MED-LGE and XLG-XXL. Choose the pair that matches your usual apparel size. If you plan to wear them inside fins, check that your fin foot pocket has room for the extra layer.

Frequently Asked Questions

Can I wear Sharkskin Thermal Flex Socks with fins?

They are thin enough to wear inside many full foot fins, but check the fit of your foot pocket with the socks on before a trip.

Are Thermal Flex socks made of neoprene?

No. They use a compression fabric with FIR technology, which keeps you warm without the bulk and buoyancy of neoprene.

What sizes are available?

They come in XSM-SML, MED-LGE and XLG-XXL.