Latin America has beaches to suit all tastes from isolated, private hideaways to large resorts with excellent facilities and nightlife. Colombia is known for its golden beaches, surrounded by lush tropical forest, or you could beach hop along the entire coast of Brazil (Atlantic) staying in pousadas or luxury resorts. Uruguay has the famous, lively resort of Punta del Este, but also some smaller, quieter beach spots further along the coast. Central America has plenty of sandy beaches - both the Pacific and Caribbean coasts of Mexico have a choice of boutique hotels or large resorts with long stretches of beach; Costa Rica has a Caribbean coast and a much more developed (and longer!) Pacific coast; and the Bay Islands of Honduras and both the mainland and the Cayes in Belize have warm seas and are excellent for diving. Don't forget the Caribbean too - Cuba has over 3,500 miles of coastline and properties vary from larger all-inclusive resorts to simple lodges.
South America: year-round (but Punta del Este and southern Brazil from November to April only). Central America is best avoided in September and October as it is the rainy season. Christmas is busy almost everywhere, so book early.
Here are some sample itineraries that feature beaches
Guatemala and Belize
Colonial cities, less travelled corners of Guatemala, jungle, Maya sites, wildlife and coast
Iconic cities, natural wonders of the world, rainforest and Brazil's north-east coast
Historic cities, the coffee-growing region and wild, untouched beaches
Classic Costa Rica
From verdant jungle and rainforest bursting with wildlife, to beautiful beaches along unspoilt coastline
Vineyards, working estancias, rolling countryside and dune-backed beaches
Ancient ruins, cloud forest, white sandy beaches and the world's second largest coral reef
A journey through western Nicaragua visiting beautiful colonial cities, stunning volcanoes and glorious beaches
Pelican’s Pouch was absolutely amazing, superlatives don't do it justice. We had two stunning blue sea and sky days, with good snorkelling, good kayaking and I even managed a hammock. I thought I might get bored, but I reckon I could have managed another day there. It is squarely on our return hit list. - SH was in Belize