What time of year? The water temperature is 66* now, and that is petty consistent Nov thru mid April. By May it is 77* and goes up to the high 80's, before cooling in November. I would not snorkel until May, -and for the most part snorkeling in our part of Florida is not particularly rewarding. (Please understand, I have been snorkeling and diving for over 75 years and have been to some of the best dive sites in the World. What I find "uninteresting, might be great for a novice.). The peninsula where you might anchor near Destin. is" controlled by Air Force as part of their "range" Along the Fort Walton area to the West. To the East, t he ICW goes inland, and no beach access. Around Destin the "go to spot" is "Crab Island-"-very crowded during the summer months. This is a shallow part of the bay with sand bottom. I am only familiar with anchorages at Joe's Bayou (and ramp), and then up inland in the Bayous which are not good diving and colder water in the winter.
I think of Destin as being a sport fisher/dive boat harbor, with night life and restaurants along the water front. One of my friends brought his 56 foot power cruiser down from Pickwick Lake for the winter. They drive down 2 x a month and spend a few days. You can anchor a number of places in Destin bay. But not a place I would swim. No beach access, but dinghy to restaurants is possible.
The best areas in my opinion are Apalachicola to St. George Island/Carabelle Some restrictions to beaches along this area. or Santa Rosa Sound to Orange Beach, pretty much where I live.
Starting in Santa Rosa Sound there are a number of fairly well protected anchorages, with good beach access. Pensacola Beach, Quiet water Beach, and Little Sabine are commercial but pleasant and one can anchor there. (watch the chart carefully for shoaling) The Fort Pickens area does have some snorkeling, but for overnighting I suggest going across Pensacola Pass to Fort McCree, where there is basin very well protected by a dredged Island and the National Sea Shore--excellent beach access. All along the Big Lagoon area, is National Seashore, and very few people. Next Is Perdido Key, then a few good anchorages until Ono Island, Alabama's Perdido Pass, Cotton Bayou, Robertson's beach etc. We live on Perdido Bay--which has some interesting anchorages, then the ICW cuts thru to Mobile Bay with no beach access. The sand or mud bottom along these areas have sea grass. The Wharf at Orange Beach has restaurants, as well as "home port" marina where Lulu's is run by Jimmy Buffett's sister. There are anchorages in some of the bayous near there.
The bridge between Pensacola and Gulf Breeze/Pensacola Beach, was destroyed by Hurricane Sally, and we don't know when it will be repaired--so launching there is probably not a good plan.
In Pensacola I would launch at Pensacola Marine Shipyard Complex--I believe $5 in and out, and a secure parking with patrols. There are free ramps, and I am not aware of any issues in the Pensacola area.
There are also a number of rivers in this area which can be explored.
To get an overview of the area go to Active Captain. Some will be dated but basically generally accurate. If you have any questions I have probably visited that area or anchorage in the 27 years we have lived in this area.