Three Fins is the third of the shallow sites near Tantabiddi named in the Aussie Marine Adventures west-side series, alongside Nick's Lumps and Floats — all reaching about 15 m, with big cracks and ledges, reef sharks, turtles and large potato cod.

No further site-specific description was located. By comparison with its neighbours, expect a reef-and-sand dive with overhangs sheltering sharks and cod, turtles cruising the reef top, and schooling reef fish. The name may refer to three fin-like reef heads or to a sighting of sharks. It suits Open Water divers.

About the west side: Ningaloo is a fringing reef, and the west side of North West Cape is where the reef faces the open ocean beyond the lagoon. Only a handful of boats dive it, launching from Tantabiddi, and much of it is rarely visited. Topography ranges from shallow cracked reef and ledges near Tantabiddi Passage to surge channels, bommies and walls further out, with 'caves, swim-throughs, huge bommies or walls, and a truly diverse range of hard and soft corals'. Whale sharks, mantas and humpback whales are seasonal visitors, and humpback song is commonly heard underwater in winter. The 2025 marine heatwave caused significant coral mortality in northern Ningaloo, so expect some dead or recovering coral. A typical west-side day combines two sites chosen by the skipper on the morning, with lunch on board inside the lagoon; because swell and wind decide everything, divers visiting Exmouth for a week should book early in their stay and keep a back-up day. The same boats often snorkel with whale sharks, mantas or humpbacks in season, so a west-side dive day can deliver megafauna on the way out or back.

Drive from Exmouth north around the tip of the Cape and south down Yardie Creek Road to Tantabiddi boat ramp, about 35 km and 30–35 minutes on a sealed road. Most operators collect divers from Exmouth accommodation by bus. Boats launch at Tantabiddi, cross the lagoon and exit through Tantabiddi Passage to the outer (west) side of Ningaloo Reef; sites close to the passage are 10–20 minutes away and further sites 30+ minutes.

Sites are chosen on the day by wind, swell and tide; boats moor or drift-dive from a live boat and divers giant-stride from the stern.

The west side faces the open Indian Ocean and takes the prevailing south to south-westerly swell and wind. Diving is only possible on days with low swell (roughly under 1.5–2 m) and light winds; strong south-westerly sea breezes (often 15–25 knots in the afternoon from spring to autumn) blow it out, so trips go early. Breaking swell on the reef crest and in the passage can make the exit dangerous.

Visibility is usually 10–20 m, but drops during plankton blooms and the March–April coral spawn — which also bring whale sharks and mantas. Humpback whales pass July–October. Cyclone season November–April.

Tidal current runs along the outer reef and through the passages.

Descend to the reef at 12–15 m, follow the ledges and cracks, and return to the boat for a safety stop.

Dive Ningaloo – Westside double-dive days from Tantabiddi (replaced Muiron trips from August 2025); Ningaloo Whaleshark-N-Dive (whalesharktours.com.au) – west-side dives; Exmouth Dive & Whalesharks Ningaloo and Ningaloo Whaleshark Swim – west-side dives when conditions allow. Whale shark tour boats also do short inner-reef dives from Tantabiddi.