This area of the Florida Panhandle provides some awesome fishing! One of the best spots we've found is under the big bridge between Port St. Joe and St. Joe Beach.
As you're leaving Port St. Joe and heading toward Mexico Beach, turn right onto the dirt road just before crossing the bridge. The road will take you underneath the bridge to the tidal creek that empties into the bay. Wade out into the bay and cast into the deep channel with finger mullet, mud minnows, live shrimp, or artificials.
This is a great spot for flounder! They lie on the bottom near the fast current of the channel, waiting for bait to swim by. I've also seen some large reds taken here, using the same angling methods.
Crabbing here is often excellent, too, and it's a good way to keep the kids entertained. Our kids have caught coolerfuls of large blue crabs along the bank without even using bait! They just walked along the narrow beach, watching for the crabs. When they saw one, they scopped it up with a long handled net.
A word of caution: Don't wade out too far! The current in the channel is deadly.
Another good spot to fish is the Port St. Joe Marina. Fish an hour before and an hour after high tide for the best results. Catches include flounder, trout, and mangrove snapper.