33957 -- U.S. ZIP code Municipality (1990): SANIBEL, Florida All ZIPs for this municipality (1990): 33957 Population (2000): 6104 Housing Units (2000): 7137 Land area (2000): 17.476341 sq. miles (45.263513 sq. km) Water area (2000): 1.483359 sq. miles (3.841881 sq. km) Total area (2000): 18.959700 sq. miles (49.105394 sq. km) Located within: Florida (FL) Location: 26.439608 N, 82.080456 W