It is not allowed in the English Channel or Catalina Channel, but it is occasionally done elsewhere in the open water swimming world from the Olympics to local beach swims.
Double capping is the practice of open water swimmers and triathletes to simultaneously use two swim caps on their head in order to solve a variety of potential issues in a race or during training:
(1) secure their goggles on their head by sandwiching the goggle straps between the two pairs of caps, (b) improve heat retention through their head especially if a bubble cap or neoprene cap is used, (c) place a required race cap on their head over their favorite swim cap, and/or (d) ensure that at least one swim cap stays on their head during the swim.
Double capping can include a silicon cap over a latex cap, a bubble cap over silicon, a neoprene cap over a cloth cap, or any other possible combination of the myriad types of swim caps.
Photo shows Benjamin Schulte of Guam competing in the 10 km marathon swim at the 2012 London Olympic Games.
Southern California native, born 1962, is the creator of the WOWSA Awards, Oceans Seven, Openwaterpedia, Citrus Corps, World Open Water Swimming Association, Daily News of Open Water Swimming, Global Open Water Swimming Conference. He is Chief Executive Officer of KAATSU Global and KAATSU Research Institute. Inductee in the International Marathon Swimming Hall of Fame (Honor Swimmer, Class of 2001) and Ice Swimming Hall of Fame (Honor Contributor - Media, Class of 2019), recipient of the International Swimming Hall of Fame's Poseidon Award (2016), International Swimming Hall of Fame's Irving Davids-Captain Roger Wheeler Memorial Award (2010), USA Swimming's Glen S. Hummer Award (2007, 2010) and Harvard University's John B. Imrie Award (1984). Served on the FINA Technical Open Water Swimming Committee and as Technical Delegate with the 2011 Special Olympics World Summer Games, and 9-time USA Swimming coaching staff. Note: WOWSA only recommends products or services used or recommended by the community. WOWSA does not receive compensation for links or products mentioned on this site or in blog posts. If it does, it will be indicated clearly on that specific post. See WOWSA's privacy policy for more information.