More than 200 Atlantic bottlenose dolphins inhabit the tidal waters between Savannah and Tybee Island year-round, their migratory patterns governed by the twice-daily lunar cycle that pulls six vertical feet of water through the marsh. The Savannah River estuary, where freshwater meets the Atlantic, creates a nutrient-rich corridor that supports shrimp, mullet, and blue crab — the prey base that holds dolphin pods in place even as temperatures shift. Commercial shrimping boats have worked these channels since the 1850s, and dolphins learned generations ago to follow the trawlers, capitalizing on bycatch and disoriented fish. Eco-cruise operators launched the first dedicated dolphin-watching routes in the early 2000s, after federal protections under the Marine Mammal Protection Act established clear distance guidelines and no-chase protocols. Today's fleet operates under Georgia Department of Natural Resources permits that limit vessel speed in designated wildlife zones and require certified naturalist guides. The sunset departure window — typically between 6:00 and 7:30 PM from April through October — coincides with the evening feeding cycle, when dolphins herd baitfish against sandbars and pilings. Sightings are recorded at 92% consistency across operators, though juveniles and mothers with calves appear more reliably in the cooler months of spring and fall. The river itself carries the visual signature of Georgia's coastal plain: tannin-stained water the color of sweet tea, framed by Spartina alterniflora marsh that turns copper in late afternoon light. Container ships share the channel with recreational craft, their eastbound passage to the Port of Savannah a reminder that this waterway remains one of the busiest on the Eastern Seaboard. Savannah sunset dolphin cruise tours thread between cargo traffic and protected wetlands, offering sightlines toward Fort Pulaski, the Tybee lighthouse, and the barrier islands that buffer the coast. Most vessels — catamarans, pontoon boats, and shallow-draft skiffs — carry between 12 and 49 passengers and depart from the River Street docks at 502 East River Street or from marinas closer to Tybee. Onboard naturalists identify individual dolphins by dorsal fin scars and explain echolocation, pod hierarchy, and the difference between transient and resident populations. The Savannah River dolphin population is genetically distinct from open-ocean pods, adapted to brackish conditions and shallow navigation.