Almost halfway between Havana (50 km) and Varadero (70 km) you'll find Playa Jibacoa, a pleasant stretch of beach seemingly isolated by the limestone hills and crags that surround it (more on those in a minute). First, the beach's main draw are its plentiful coral reefs that begin so close to shore they're nearly uncovered come low tide (no exaggeration). This has made Jibacoa an easily accessible destination for snorkelers and divers, who can often set out to explore the island's rich sea shelf right from the shore. Depending on who you ask, there are between 8-15 mapped dive sites, stretching as far the grottos and coral gardens of Puerto Escondido 15 km east. Visibility here, as with much of Cuba, is around 25 m on a bad day or when the tide is kicking up sand, with no shortage of marine life (eels, spiny lobsters, all kinds of fish, etc.) and dive shops aplenty (Cameleon Villas and Breezes Jibacoa are two easy options, the latter providing a boat for early morning deep dives between 30-40 m)
If you prefer your challenges to take you in the opposite vertical direction, Jibacoa has also become something of a new hot-spot for Cuba's nascent (and still technically unauthorized) sport climbing industry. The aforementioned crags such as El Peñón and El Peñón del Fraile already offer somewhere around 20 bolted routes and counting, ranging in difficulty from 5.8/5.9 through the 5.11s. The runs are a bit scattered, and you'll need to do some savvy navigating with locals in order to help them turn a blind eye to your activities, but if you're fluent in Spanish or have a knowledgeable guide with you this won't be an issue. And just bear in mind that though these climbs don't afford the same beautiful views as Vinales, a picturesque ocean backdrop is never a bad runner up.
Note:Due to the proximity of the corals, take great care when snorkeling/diving/kayaking so as not to inflict any more damage than is annually done by the resort goers here. And if you'd prefer to keep things low-budget, look for the available bungalows/campsite at Villa El Abra.