Reviewed: Orca Aesir Flex Swimrun Wetsuit

Orca says:

The Aesir Flex wetsuit is the most elastic wetsuit in the Orca Swimrun range. It has a vest-like construction for optimal performance in both running and swimming. The 40 + technology provides more flexibility, without sacrificing durability, thanks to the outer fabric of the legs.

We say:

The first thing we noticed about the Aesir Flex was its weight – or rather, the lack of it. It immediately feels designed for speed. We tested this initially in a pool. Without shoes, race vest or race belt, swimming is comfortably faster than without a suit, almost matching the speed of a full swimming wetsuit. Out on the trails, running feels natural and unrestricted.

After basic testing in training, we put the wetsuit through its paces in the Wales Swimrun, which in 2023 had 28km of running and around 4.5km of swimming. Conditions were tough with persistent wind and rain and water of around 16 to 17 degrees. I added Orca swimrun arm sleeves for additional warmth and wore a thin fabric triathlon vest underneath. I was comfortable throughout: never too hot nor cold and had zero chafing. I also appreciated the cleverly designed front zip that separates fully at the bottom allowing you to open the wetsuit more widely than usual. This makes it easier to open up and/or roll down while running.

The one thing missing on this suit is pockets. It has one internal pocket at the back but this is tricky to reach. You will therefore need to find other solutions to carrying any compulsory kit and nutrition. One option is the Orca Swimrun Race Belt, which has a generous zip pocket big enough to hold a small drinking flask and some gels. I used a triathlon vest beneath the wetsuit that had a couple of pockets. You could also try an Orca Neoprene Swimrun top, which not only adds 1.5mm of neoprene but also includes two mesh pockets.


Lightweight, fast, flexible and comfortable. Ideal for racing in mild to hot conditions.


Lack of pockets. Thin. An extra layer may be needed in cooler water.

Alternatively, for racing in cold conditions, check out the Aesir Thermal Swimrun Wetsuit.

Price: £449 from  BUY NOW