Two surfers compete against each other in a standard head-to-head World Surf League heat.
Each competitor catches waves during the allotted time, and judges score the best rides according to criteria such as difficulty, speed, power, flow, and the quality of maneuvers. The surfer with the higher combined score advances or wins the heat.
Earlier rounds or special event formats can use different structures, including heats with three or more surfers. However, the familiar head-to-head format places two surfers in direct competition and makes the result easy to understand.
A heat is not the same as a single wave. A surfer may ride several waves during one heat, while only the best required scores count toward the final result under the event’s rules.