Last year I bought a swimskin for Ironman Louiseville. Unfortunately, Team K&G had to withdraw from Ironman Louiseville and I never had the occasion to use it. A few weeks ago at a local Olympic distance race I finally had the opportunity to swim in a swimskin. I loved it.
A swimskin, also referred to as a “speedsuit,” is a technical swimming suit designed to be worn over your normal triathlon race kit for swimming. They are sleeveless. Some have full length legs and some end above the knee. Unlike a wetsuit, a swimskin will not provide buoyancy or warmth. Since swimskins do not provide buoyancy and are typically only “shortjohns” they do not enhance speed to the degree a wetsuit does. However, swimskins may be worn for swims when water temperatures are too warm for wetsuits, which for USAT and WTC is 76 degrees. Not all swimskins are permitted in USAT events are permitted in Ironman events (at least as of last year). Swimskins permissible in Ironman events must be made of fabric, as opposed to neoprene or rubber. They also may not go below your knee. In US Masters Swimming swimskins are considered “Category 2” swimwear. They are not permitted in pool swimming and are only permitted in specific open water events.
The race I tried the swimskin at was a “B” race. I wanted to experiment with a few things, the swimskin being one of them. My swimskin, the Tyr Torque, is made of the same fabric as my tri kit, a Tyr Carbon. The fabric sheds water like crazy, but a swimskin is cut differently. It is tighter and fits much higher on the neck so it does not catch water. Swimming in the swim skin felt fast and very natural; much more natural than swimming in a wetsuit. It fit tight and prevented by tri kit from catching water and creating drag. Based on my typical Olympic distance swim splits, the difference between swimming in the swim skin and swimming in a wetsuit was about 2 minutes. My wife swam in her kit, also a Tyr carbon, without a swimskin and her kit caught water like a parachute. If anything, she lost time by swimming without a swimskin.
There are tri kits that can double as swim skins. ITU-style trisuits make good swimskins, but they often lack pockets and a chamois. A swimskin’s fabric and fit may also be too tight to comfortably ride and run a half-Ironman or Ironman. Swimskins also have a back zipper, which creates less drag for swimming, whereas most tri kits designed for long course racing have a front zipper. The bottom line is that, in general, tri kits that are good for swimming are not as good for cycling and running, especially in half-Ironman and Ironman distance, and that tri kits good for long course cycling and running are rarely good for swimming. In a long course race that is not wetsuit legal a swimskin, coupled with a long distance tri kit, is ideal.
I am not qualified to assess whether one swimskin is faster than another, but, based on my experience I can say that the difference between swimming with and without a swimskin is likely much larger than the differences among swimskins. In northern California, races were wetsuits are illegal (and the RD enforces the temperature rules) are rare. Even a “basic” swimskin will work and give you an advantage. If you anticipate races where wetsuits will not be legal I highly recommend one.