The list of items essential for surfing can be counted on one hand: surfboard, swimsuit, board shorts or wet suit. Maybe a leash. Likely a watch.

“It’s a staple piece,” said Coco Ho, a professional surfer from Hawaii and for 14 years a Proteam athlete, one of Swatch’s groups of ambassadors. “A watch is a tiny little instrument on your arm, but it’s got a big personality.”

While watch brands such as Swatch and Freestyle have decades-long involvement in surfing, a wave of more mainstream timepiece companies newer to the sport, including Tudor, Breitling and TAG Heuer, have been increasing their participation. Since becoming more organized in the early 2010s and an Olympic sport in the 2020 Games, what was once a sport partially owned by surfers has grown to be big, corporate business.

It is easy to imagine how brands could be attracted to a picture-perfect day at the beach — glistening blue ocean, surfers dancing on waves.

But it is specifically women’s surfing that has built new audiences and, as a result, drawn brands. “Women’s surf has been growing fast over the past 50 years, but has recently gained much more visibility as well as equality,” Alain Villard, chief executive of Swatch, wrote in an email.