Lacanau-Ocean is the seaside part of the village Lacanau although they are seperated by about 2 miles.  If flying in via Merignac airport find Methard En Jalle and follow the signs from there (about 45 mins). Lacanau, the village, is a sleepy spot.  All the fun is down in Lacanau-Ocean.  The beach has a custom built resort with the usual numbers of bars (The Kayoc on the seafront is recommended for cocktails and sunsets ) and restaurants.  Behind this is a huge number of holiday homes and camping sites (although you wouldn't know it as they are hidden in the forest that covers most of Acquitaine).  Holidays here are about activity - several golf courses, cycle paths everywhere (really ! - everywhere), forest walks, and amazing surf.  The sea is very dangerous and only the most skillful swimmers should try it but the waves are a haven for body boarders, surfers and power kiters.   Carcans beach is quiet and clean. There are a few cafes and a surf shop at Carcans plage.  By the way - hiring a car is a great idea, nearly a necessity.  If you don't like the sea there are 2 vast inland freshwater Lakes for swimming, boating and sailing.  Market day is Wednesday and there seems to be a business half day on Tuesday.  This is a resort for surfers but also families.