I found this for you
Miami, South Beach, Florida, Beaches ,Caribbean, Pet Tips, Parks that allow Dogs
My parents live in Sarasota and we went to a doggy beach in Dec. in Venice, but next time we will be going to a beach in Sarasota that a member on YT told me about.
The biggest issue for us, were all the big dogs - no one was aggressive, but some rushed my dogs. Keep your eyes on your dog at all times, if you have more than one, get someone else to walk the shore with you, because my 2 didn't always want to stay together. Fresh water is a good idea. I came with bags, etc. although they were there to be found too
Here they were in Venice: