American River is a small fishing and holiday town on the narrow neck of the Dudley Peninsula, where a tidal channel links Eastern Cove with the shallow, bird-rich Pelican Lagoon.

The habitat is sand, seagrass and channel edges, with oyster leases nearby. Tidal flow brings food into the lagoon, supporting seahorses, pipefish, razorfish beds, rays, juvenile fish nurseries and crabs, and cuttlefish and squid hunt along the seagrass margins. Pelican Lagoon itself is a conservation park and important bird habitat. The water can be clear on a high-water slack when Eastern Cove water floods in, and green and murky on the ebb.

Published diver information is thin, so conditions and depths are estimates. The key rules are simple: dive around slack water, keep clear of the boat ramp, wharf and commercial oyster leases, and use a surface float. The Red Banks snorkel spot, which Tourism Kangaroo Island lists with sandy seagrass shallows and deeper reef for experienced swimmers, is about 15 minutes' drive away. American River suits divers who enjoy macro and seagrass critters and want a sheltered site on the east of the island. Pelican Lagoon's birdlife, the town's oysters and the nearby Red Banks and Pennington Bay make American River a good base for exploring the eastern half of the island. Night dives at slack water can be especially productive for cephalopods and crustaceans.

Take the SeaLink ferry from Cape Jervis to Penneshaw (45 min). From Penneshaw drive about 30 km (25 minutes) west on the Hog Bay Road to American River, or 37 km east from Kingscote. Park on the township foreshore near the wharf and boat ramp, gear up at the car and enter from the shore at a spot clear of the boat ramp and oyster leases.

Plan around slack water because the channel runs strongly on the tide.

Sheltered from ocean swell inside Eastern Cove, so weather rarely prevents a dive, but the tidal channel into Pelican Lagoon runs strongly: dive only around slack water (high-water slack gives the clearest water), and avoid spring tides. Strong easterly winds create chop across Eastern Cove. Visibility drops on the ebb as lagoon water drains out, and after rain.

Enter at slack water, drift slowly along the seagrass edges and channel margins in 2-6 m looking for seahorses and pipefish, and exit before the tide turns; tow a float.

No regular operator; Kangaroo Island Dive & Adventures (Kingscote) – guided dives and advice (confirm current trading).