Progreso is the Gulf beach town for Mérida, close enough for a day trip but different enough to feel like a change of climate. The water is shallow, the sea breeze is real, and the long malecón fills with families, seafood vendors, and cruise passengers when a ship is in port.
The town's oddity is scale. Its cargo and cruise pier runs far into the Gulf because the coast is so shallow, while the Chicxulub impact that helped end the age of dinosaurs happened just east of here. The Meteorite Museum turns that cosmic accident into an easy stop on the waterfront.
Progreso is not the Yucatán's prettiest beach, but it is a good one-day mix: swim or walk the malecón, look out at the pier, eat fish by the water, and use the town as a base for Xcambó and the flamingo ponds near Uaymitún.