We'll be in St. Lucia in April and hope to rent a villa for our family, including three children ages 11 months, 3 years, and 5 years. We want to be able to drive to beaches with generally calm, clear water and gradual drop-off. I have not been able to find out which beaches would meet our needs and where those beaches are on the island. Any help will be appreciated.

Reduit Beach has clear water and was calm when we were there. It's north of Castries.

My wife and I stayed in Marigot Bay in fall of 2006. We rented out The Great House. http://www.oasismarigot.com/
You can walk or drive down the hill to get to a water taxi that takes you across the shallow bay to the beach. There are also some great local restraunts in the bay including everything from pizza to steaks to seafood. The best part about the location is that Marigot bay is pretty centrally located on the island.

The beaches on Pigeon Point are very calm. (They're a 5 minute drive from Rodney Bay.) Smugglers Cove in Cap Estate (5 minutes further north) is very calm, but you have to walk down about 75 steps to get there, which might be an issue with young kids. The beach at Windjammer Landing is also very nice for young kids. By the way, all of the beaches in St. Lucia are open to the public, including the beaches at the all-inclusive adults only hotels. We take our 4 year old kids to the beaches at the Sandals Resorts all the time. However, the kids can't use any of the hotel facilities, including the bathrooms.