The amphibious vessels departing Tidal River can cross sand, ford shallow creeks, and transition directly into deeper water without a jetty. This capability emerged from the park's geographic reality: no deep-water harbour exists at Tidal River, and the coastline shifts with every storm. The first commercial wilderness cruises launched in 2011, using military-surplus vehicles retrofitted with marine-grade hulls and cabin enclosures. By 2018, purpose-built amphibious craft replaced them, carrying twenty-six passengers and equipped with hydrophones for live whale-song transmission during migration months. Wilsons Promontory sits at the southernmost tip of the Australian mainland, a granite massif jutting into Bass Strait. The coastline beyond Tidal River—accessible only by sea—comprises vertical cliffs, wave-sculpted caves, and a chain of uninhabited islands where Australian fur seals haul out in colonies numbering several thousand. Waterloo Bay, Refuge Cove, and the Glennie and Anser island groups form a marine sanctuary closed to private vessels but open to permitted operators. The wilderness cruise from Tidal River covers roughly thirty-five nautical miles in a three-hour loop, threading between submerged reefs that claimed seventeen ships between 1840 and 1920. The granite here is Devonian, four hundred million years old, and weathers into spheroidal boulders that stack in chaotic formations along the shoreline. Marine wildlife density around the Prom peaks during the southern right whale migration, June through October, when calves are nursed in sheltered bays. Year-round residents include bottlenose dolphins, which often bow-ride the amphibious vessels, and white-bellied sea eagles nesting on offshore stacks. The seal colonies are matriarchal; adult bulls arrive only in November for breeding season. Park Victoria monitors population health through annual aerial surveys, and the 2025 count recorded 8,400 seals across the Prom's offshore islands, a recovery from fewer than 200 in the 1960s when hunting ceased. The amphibious departure model solves a problem that constrained tourism here for decades: Tidal River's beach is too shallow for conventional boats, and constructing a pier was rejected on ecological grounds. The vehicles board passengers in the campground carpark, drive across the beach, and enter the surf zone at walking speed. Once afloat, twin outboards engage and the hull planes at eighteen knots. The transition takes ninety seconds. No other national park in Victoria offers this access profile. The vessels carry Parks Victoria-accredited guides who narrate geology, shipwreck history, and real-time wildlife sightings. Hydrophone feeds are routed to overhead speakers, so passengers hear seal vocalizations and, during winter months, the low-frequency pulses of migrating whales even when the animals remain submerged. The cruise operates year-round, weather permitting, with departures from Tidal River scheduled around tide windows that allow safe beach transit.