Board shorts are a type of swimwear commonly used by surfers and others engaging in aquatic board sports. "Boardies," as they are sometimes referred to by the surfing community, are lightweight and durable. They are usually made of nylon or a smooth polyester material to stand up to wear and tear due to contact with a surfboard.
Option 1 - Traditional and Bare
Board shorts are designed to be worn as is, with nothing under the garment. Some sportswear designers have begun to line the inside of their board shorts with a mesh liner, to provide support similar to a traditional swim short and address complaints from swimmers or fashion-conscious beach goers who do not surf. Many surfers, however, feel that this type of liner causes irritating friction and will tear it out if they choose to purchase a lined board short.
Option 2 - Boxer Shorts or Boxer Briefs
Some surfers choose to ignore tradition and will wear boxer shorts or boxer briefs under their board shorts. For those who use board shorts as swimwear or for casual beach wear, this is one alternative. The other is to purchase a board short-style swimsuit, which has a mesh liner on the inside.
Option 3 - Lycra Shorts
Avid surfers or those with more sensitive skin sometimes complain of discomfort or rashes that develop while surfing only with boardshorts on. The most popular alternative is to purchase Lycra/spandex shorts and wear them under board shorts or wet suits. The skin-tight Lycra shorts are designed to lock out sand and keep in warmth.