Swimwear for Open Water

There are 2 categories.

Category 1

• Suits can only be made from textile materials. 
• For men and women:
  • the swimsuit shall not cover the neck and shall not extend past the shoulder nor below the ankles. 
  • the swimsuit can not contains clasps or zippers.
• No rashguards.  No armbands.  No tape on the body.

Category 2 (other swimwear and wetsuits)

• All other swimwear (e.g. wetsuits, last year’s technical suits like Blue 70’s, rash guards and arm bands.) are permitted.
• No type of tape on the body is allowed, unless approved by the event director or event referee. 
• Once the water temperature reaches 78 degrees, wetsuits are not allowed.

Rules for both Categories  

• Allowed:  Cap(s), neoprene caps, nose clips, ear plugs, wristwatches and grease.
• Not Allowed:
  • Any device or substance that helps your speed, like webbed gloves, fins, snorkels.
  • The use of any kind of tape that purports to provide muscle compression; muscle, joint,  or  ligament  stabilization;  or  other  physical  benefits,  including  therapeutic elastic  tape  or  similar  products, is never permitted in USMS competition.

From: USMS Open Water/Long Distance Rules
http://www.usms.org/rules/part3.pdf

Additional clarification on the use of tape:
https://www.usms.org/rules/20160626_therapeutictape.pdf