Its a hike from Naples, but the best shore dive along that coast is at the south end of Gasparilla Island (Boca Grande). There is an old Phosphate dock on the edge of deep water, 10 ft on the inside and 30-40 on the outside. Look it up on Google Earth. Huge numbers of fish, all the sheephead you can spear, plus lots of other stuff that is either hard to shoot or off limits, including lots of 50-300 lb Goliath grouper. A very fun place right next to shore. You need to get there 30 minutes to an hour before slack current at high tide. Current is too strong to dive otherwise. Internet has current tables (not just tide tables). Vis is not great, 10 ft-25 ft, but it is a fun place. I've always dived it from a boat, but check the shore access, it should be easy.