Hi Ian,
Several beach destinations abound in Venezuela, as it's coastline is very long. Most popular beach destinations are, as mentioned above, Los Roques, Margarita, Choroni, Morrocoy and Mochima. Los Roques and Margarita are easiest to get to by plane, so If you are looking to arrive in Vzla and head straight of to the beach then these destinations could prove to be good options. Los Roques is very small, very nice, no roads, great beaches, a nice laid back town with nice posadas and good food. Margarita is much bigger, plenty of roads, even highways, it boasts some very nice beaches, great restaurants, some awesome night life and plenty of adventures sports such as Kitesurfing and diving.
Choroni, Morrocoy and Mochima are easier accessed by car, but they are quite a drive from Caracas International Airport. Choroni, being the closest. Its perfect location in the middle of the Henri Pittier National Park make it a great attraction for beach lovers and mountain trekkers alike.
There are some very nice off the beaten track destinations which are just mesmerizing. Isla La Tortuga is one if them. Quite pricey to get too, but once there you will realize that Los Roques is - just another beach compared to La Tortuga. You may want to look into Puy Pui, Playa Medina and whereabouts, located beyond Rio Caribe in the Eastern section of Venezuela.
Hope this information is of help to you.
Travel safe,
All the best,
Thomas
berry_venezuela@hotmail.com
Caracas