Thermal wetsuits: 2 of the best for triathlon reviewed

Feel the cold or have some cold-water swims/races planned? Then a thermal wetsuit could be just the thing for you. Matt Baird reviews two of the best

Credit: The Secret Studio

Blueseventy thermal reaction



Blueseventy became cold-water wetsuit pioneers when they launched the Helix Thermal (£600) to great acclaim in 2016. And for 2018 they’ve launched the slightly cheaper Thermal Reaction (£495).

The Thermal Reaction boasts the same zirconium liner used in the Helix, providing a plush and fluffy feel on the body that’s proven durable after a couple of seasons’ use. We used it in temps of 6.5°C and 8°C, but Blueseventy pitch it for a minimum of 8.5C. And yet the suit still performed admirably in the bracing water, limiting water ingress around the neck and through the zip. How much comes down to a psychological boost is open to question, but we really felt the warmth benefits of that soft zirconium liner.

The 5/5/4mm neoprene thickness is only marginally different to the 4/5/4mm of the conventional Reaction (with an extra millimetre on the chest) and produces a buoyant suit, but not one compromised by flexibility and the upper body is especially lithe. It’s quick to remove, and we’ll be using it at the Slateman in May. We’d now like to see if the zirconium tech can be applied to their £275 Fusion suit, opening up the thermal benefits to a wider audience of swimmers. MB

Verdict: a brilliant suit gets the thermal upgrade with warmth-gaining effects 92%

Buy from

Huub Aegis II Thermal


Huub’s entry into the thermal wetsuit market is their mid-level Aegis II, which showcases the Derby brand’s winning buoyancy mix of 3mm core/5mm leg neoprene thickness. We’ve long been fans of the standard Aegis, but it’s tighter across the chest than the Reaction – a theme with Huub suits, so keep an eye on sizing – and the thermal variation isn’t easy to get on (not helped by the breakaway zipper), which frustrated us while trying to retain some warmth pre-swim in a windswept beachside car park. 

In the water, however, the Aegis – when swimming well – felt swifter than the Reaction, aided by that lean fit, Smoothskin coating and that buoyancy profile. But in terms of thermal properties? Less so. While still evident, we just didn’t feel as protected from chills in the Aegis II, with the internal 0.7mm nylon/polyester lining lacking the warm blanket feel of the Reaction. We also felt more water ingress through the zipper. But if you suffer from the cold, we can see the benefits of using the Aegis Thermal during the season, and combined with Huub’s Varme Thermal Balaclava (£34.99) it offers a more affordable package than the Reaction. MB

Verdict: still a fine and fast suit, but it just lacks the warmth of the reaction 80%


Buy from

Triathlon wetsuits: 14 of the best tested and rated