Mexico offers a great chance to combine resort amenities, beautiful beaches, plus cultural interest such as Mayan history. The Mayan Riviera in particular offers this combo of all inclusives plus coral reef plus Mayan ruins.
Families love to vacation at beach resorts in Mexico, especially at all-inclusives that offer watersports, kids programs, entertainment, and of course meals, snacks, and drinks. Below find several of Mexico's best spots, west coast and east, including two areas just coming onto the tourist radar.

Photo courtesy of Cancun Convention & Visitors Bureau.Cancun is on the east side of Mexico, with shores on the Caribbean Sea. Decades ago, this unique area -- with double waterfront, ocean and lagoon-- was picked by the Mexico government as Mexico's best spot for tourist development. And they got that right: today Cancun has a busy 25-km Hotel Zone and gets 20% of Mexico's tourism.
The 130 km stretch of coast south of Cancun extending to Tulum-- is arguably Mexico's best destination for family beach holidays. All-inclusive resorts dot the coast, with all the usual amenities plus some elaborate pool complexes. Outings are terrific: snorkeling on the second-largest barrier reef in the world;visiting the extensive ruins at Tulum and Coba, where kids learn about Mayan history; day-trips to unique "eco-archeological" theme park, Xcaret, or sister park Xel-ha, or to "cenotes"... So much to do.
This area -- south of the Riviera Maya-- is starting to attract visitors. Families will have a fairly long drive down the coast, and won't find any large all-inclusives -- which may be just what you want, a place that's not overly developed yet. Several small hotels and inns welcome kids. Enjoy uncrowded beaches, peace and quiet, Mayan ruins, an underwater National Park, and the unique Sian Ka'an Biosphere Reserve.
Moving over to Mexico's west coast: Mazatlan has been one of Mexico's best tourist draws for decades, and has long stretches of beach, a historic downtown, a busy tourist zone, an aquarium, water park, and reputation for sportsfishing. Families can find a couple of "playas" (beaches) with calm waters; in other areas, kids can learn to surf.
South of Mazatlan and north of Acapulco, about mid-way on Mexico's Pacific coast, Puerto Vallarta has nearly 30 miles of golden sand. Watersports include snorkeling
and surfing, plus kayaking, windsurfing,parasailing, sportfishing. Visitors can explore an old town with cobblestone streets, and ogle the mansions that belonged to Elizabeth Taylor and Richard Burton back in the days when they put "PV' on the map. Jungle and canopy tours are nearby.
Until recently, the stretch of Mexico's west coast north of Puerto Vallarta was an off-the-beaten-path area where surfers might go for an unspoiled break. Now, this 130 mile stretch of coast and lush tropics is called the "Riviera Nayarit", and more visitors are coming to enjoy its white-sand beaches, many of which have good surfing. Some resorts have been built, but development is still at an early stage - which may be just what some families want. (And you
can find serious pampering, plus kids club, at the Four Seasons Resort Punta Mita.)

Photo courtesy of Hilton Los Cabos.The long Baja California peninsula extends about half-way down the west side of Mexico, and at the bottom tip sits this popular vacation spot. Los Cabos has two "Cabos" ("Capes"): San Jose del Cabo, and (party-town) Cabo San Lucas, connected by a 17-mile "Corridor" with resorts and golf courses. Los Cabos offers whale-watching in winter; some good snorkeling; horseriding; and sightseeing in the artists' town of Todos Santos. Currents can be strong at the beaches, so choose your resort carefully if you want a swimmable beach.