Isla Mujeres

Isla Mujeres is Cancún's pressure valve: a seven-kilometre sliver of island twenty minutes across the bay by ferry, where the hotel zone's towers shrink to a skyline and the pace drops to golf-cart speed — which is literal, since renting a cart and circumnavigating the island is the organising activity of every visit. The Ultramar ferries run from Puerto Juárez (and hotel-zone piers) every half hour; the crossing itself, past turquoise shallows with the towers receding, does half the de-stressing before you land.

The north end holds the headline: Playa Norte, routinely ranked among the world's best beaches for a specific engineering reason — a shelf so shallow and calm you can wade a hundred metres out with the water at your waist, palm-leaning, swim-up-bar adjacent. It's busiest noon to three when the day-trippers concentrate; ferry over early or stay for the sunset (the rare Caribbean beach that faces west) and it earns the rankings. The town behind it is sarong-shops and taquerías; eating where the menus lose their English, two streets back, upgrades lunch instantly.

The south end is the counterweight: Punta Sur's sculpture-dotted cliffs — the easternmost point of Mexico, first to catch the sunrise — with the small Ixchel temple ruin (the goddess whose figurines named the island) and crashing wild-side surf. Just before it, Garrafón: the reef park built into the cliffs, whose day pass bundles snorkelling the shallow reef, kayaks, the zipline over the sea, and lounger-and-lunch infrastructure — the packaged but genuinely scenic way to do the island's water sports in one place, best booked online ahead rather than at the gate.

The assembly: earliest ferry, cart rental at the dock, south loop first (Punta Sur and Garrafón before the heat), long Playa Norte afternoon, dinner in town, sunset ferry back — the best simple day in the Cancún orbit, and the antidote to it.