On some beaches, especially during the winter and spring, worn and broken shells can pile up in mounds. Walking on these sharp shells can be uncomfortable. This seems to occur more frequently on the peninsular west coast of Florida. Certain beaches seem particularly prone to the accumulation of shells. Anna Maria Island, Lido Key, Bonita Beach, and Sanibel Island are a few beaches on the west coast that at times have a lot of broken shell on the beach.

Atlantic beaches tend to have less shell, although some do have large limestone rock on the beach that isn't for walking on with bare feet. Here's a partial list of some super white soft sandy beaches: Destin and Fort Walton Beaches, Panama City Beach, Clearwater Beach, Longboat Key, the northern half of Siesta Key, and Marco Island.

Keep in mind that when new sand is brought in from offshore to rebuild eroded beaches, the quality of the sand varies. Sometimes it contains a lot of broken shell, sometimes it is soft and white. So any given beach can experience a range of sand types depending on the time of year and whether any new sand has been introduced recently.

If you find yourself on a beach with a lot of shells, you might be more comfortable wearing a pair of beach-shoes or flip-flops. Any time that you go for a long walk on the beach, I recommend at least carrying some footwear with you, even if you don't start your walk wearing it. You may find you need it later.

If you want a beach that's really sandy and has few sharp shells, northwest Florida beaches (a.k.a. “panhandle”) will make you happy. Also consider Clearwater Beach, Longboat Key, Siesta Key from Crescent Beach northward, and Marco Island. On the Atlantic Coast most of the beaches are pretty easy on the feet, although I do recall finding some small rocks in the sand near the water in the Miami area that were a bit uncomfortable on my bare feet.