Smathers Beach is definitely the longest stretch of white sand beach in Key West. It runs along South Roosevelt Boulevard for almost 2 miles on the south side of the island. This beach has everything but lifeguards. Vendors with vans pull up to the curb selling food and drink and there are vendors on the beach renting kayaks and beach equipment. There's also volleyball nets, and a magnificent view of sunrise.
A steady procession of people parades up and down the extra-wide sidewalk that parallels the beach on bikes, skates, and on foot. The beach itself is fairly wide with excellent white sand, lush coconut palms, and shallow water that is great for swimming and basic snorkeling. There are public restrooms and showers to rinse off.