Folly Beach residents and visitors can catch and enjoy seafood all the year.
This explanation assumes that you have no boat.

Mainly Fin Fish Links

For local fin fish information, join the Folly Beach Anglers: https://fbakt.org
The Anglers sponsor “Take a Kid Fishing Day.”

Walk the Folly pier to be among local fishers who gladly share information about what kind of fish and when.
Find a formal report of what’s in season, along with charter advertisements:
https://fishingbooker.com/reports/destination/us/SC/folly-beach

Stroll into a Haddrell’s store to find reliable information, durable equipment, and local seminars and events:
The nearest Haddrells is 47 Windermere Blvd, Charleston, SC 29407: https://goo.gl/Mbfm6h
See their selection of equipment and events at: http://www.haddrellspoint.com/blog/category

Licensing

Beware offhand reports as to what is required of licensing. Regulations change yearly. Clerks in big-box retail stores often lack comprehensive or recent information. Pricing of licensing may be dependent upon whether you are a resident.
People 65 or older may purchase a “lifetime” fishing license. It does not cover baiting for shrimp.
http://www.dnr.sc.gov/licenses/pricingresident.html

Gathering Crabs, Shrimp, Oysters, and Clams

Crabbing is the most successful gathering activity. The easiest form of crabbing is with drop nets:

Crabs are available in shallow waters (no boats required) from May until early November.

Shrimping

Gathering juvenile shrimp in shallow waters (no boats required) with cast nets is normally done beginning mid-July and into early November. Casting also may catch a few fish, typically mullet, and crabs. If new to casting, purchase a cast net from a specialized fishing store. It will cost more than from a big box store but will last longer, have a longer hand line (throws further), and be easier to cast. One with a 5-6ft radius works well for beginners. Normally, nets will have a how-to video or give URLs for instructions. YouTube has videos as well, though they often emphasize heroic casting of large nets.

“Baiting” for shrimp normally begins around September 15 and lasts a month. Baiting may be done from a dock, but it usually is done at night from a boat. It requires a specialized license.

Oysters and Clams

Season: October 1 through May 15, unless conditions warrant shortening or extending the season. Check your local newspaper or call the South Carolina Department of Natural Resources at (843) 953-9300 for dates.

Overview of regulations: http://www.dnr.sc.gov/marine/shellfish/regs.html

Once you have your saltwater license and are going to gather oysters and clams, check first with closures by the Department of Health and Environmental Control. These bivalves filter water and thus concentrate anything in the water. Lots of rain produces runoff from roads and yards, making them unsafe to eat.
http://www.scdhec.gov/FoodSafety/ShellfishMonitoring/Map/

The map currently most relevant to Folly for gathering on public grounds is the 10A series:
http://www.scdhec.gov/foodsafety/docs/SFMA_10A.pdf