Are Thermal Caps, Socks (Booties) or Gloves Legal in Triathlons?
The legality of wearing thermal caps, socks or gloves depends on whether it's a USA Triathlon or Ironman branded event and also the style of sock or glove. Ironman tends to be more strict compared to USA Triathlon's rules.
Gloves: Any style glove will result in DQ in Ironman. But USAT allows non-webbed gloves. For example, these Blue70 Thermal Gloves would be legal.
Caps: Thermal caps are allowed for both organizations when wetsuits are also legal (if the water is below a certain temperature).
Socks/Booties: Thermal Socks are allowed for both organizations when wetsuits are also legal and if they don't aid in propulsion.
Here are the 2022 Ironman Rules:
Here are the 2022 USA Triathlon Rules: