wear rash guards with long or short sleeves. Some organizations and promotions, like IBJJF, require the participants to wear a solid color - usually black, or black with at least 10% of their belt color. Other organizations allow the competitors to wear a rash guard of their choice. The same rule goes for gyms and academies with each one setting their own requirements from their students. See also Glossary of surfing References Swimsuits Shirts