Adding to surfing’s taboo image was a Cuban report linking surfers to the international spy game. In 2011, the state-run newspaper Granma reported that members of a C.I.A.-backed nongovernmental organization tried to smuggle banned satellite equipment into Cuba. Dishes were festooned with fake fins and broad stripes to replicate bodyboards and skimboards. The group tried to use the surfers as middlemen, even going so far as to stage a fake surf event in Baracoa, on the eastern end of the island, to create an air of legitimacy. The mission was eventually “uncovered” by a Cuban double agent.

To help improve surfing’s image, Valdes and Cording organized good-will missions on behalf of surfing. Last Christmas, Valdes brought $800 of food and goods to a Havana orphanage with money raised by Royal 70 in Australia. Havana surfers also regularly organize beach cleanups around the city. And most important, they continue surfing without creating problems for government officials.

“The government struggles with the idea of surfing,” said Cording, who works with Cuba’s sports ministry to negotiate the flow of donations. “It is such a new idea to them. If we tell them what we’re doing, they’ve pretty much said they are very in favor of having surfing grow on the island. But they don’t want to support it financially. So they said do it underground and we’ll turn a blind eye.”

Being allowed to develop on their own has opened the doors for surf-related donations to trickle in, with the help of Royal 70 and other travelers. For example, an Australian rugby team called the Warringah Rats recently visited Cuba to play exhibition matches. The Rats planned to bring boards, leashes, videos and wax to donate to Havana’s surfers.

Nearly all donations travel through Valdes. His place in the Playa neighborhood of Havana, a cramped three-room apartment up five flights of unlighted stairs, is the closest thing in Cuba to a Western surf shop. Donated equipment, shaping tools, boards in need of repair and a few treasured magazines are scattered throughout his living room. But true to the revolution, everything is shared free. Valdes maintains a list of people who want boards. When a new shipment arrives, he distributes the boards to the next people on the list, with one condition: if they have an old board, they must pass it on to another person on the list, at no cost, and so on.