The boat to Fort Sumter leaves from the City Marina. To get to the City Marina from US 17 in Charleston exit from US 17 onto Lockwood Drive south and go about 0.3 miles to the marina.
Birds to look for
Lesser Scaup (w), Bufflehead (w), Common Goldeneye (w), Red-breasted Merganser (w), Red-throated Loon (w), Common Loon (w), Horned Grebe (w), Northern Gannet (w), Brown Pelican, Double-crested Cormorant, Osprey, Bald Eagle, Merlin (fall), Peregrine Falcon (fall), American Oystercatcher, Ruddy Turnstone, Purple Sandpiper (w), Laughing Gull, Bonaparte's Gull (w), Ring-billed Gull, Herring Gull, Lesser Black-backed Gull (w), Great Black-backed Gull (w), Gull-billed Tern (s), Caspian Tern, Royal Tern, Sandwich Tern, Common Tern (spring, fall), Forster's Tern, Least Tern (s), Black Tern (fall), Black Skimmer
One way to see some of the birds of the Charleston Harbor is to take the ferry out to Fort Sumter. At the fort itself you might find a few migrants, especially in fall. In winter there is a chance for Purple Sandpiper.