The name describes the habitat: a lower-relief bottom carpeted with sponges, sea whips and gorgonians rather than a high coral reef, swept by the tidal currents that run around the islands.

Sponge gardens in the North West Cape area are rich in filter-feeding life and the small animals that live among them — nudibranchs, feather stars, crabs, shrimps and small fish — while the current brings trevally, mackerel and reef sharks. Because sponges are less vulnerable to thermal bleaching than hard corals, this style of habitat may have fared better than coral reef in the 2025 marine heatwave, though that has not been confirmed.

It is run as a live-boat drift and suits divers with some drift experience. Little detailed published information exists; check with operators for its current use, particularly while Dive Ningaloo's Muiron pause continues.

About the Muirons: North and South Muiron are two low, uninhabited limestone islands about 15 km north-east of the tip of North West Cape, protected within the World Heritage-listed Muiron Islands Marine Management Area. They are reached only by boat, which has kept the surrounding reefs relatively untouched. The waters are visited by dolphins, dugong, pilot whales and, from July to October, migrating humpback whales, and turtles nest on the island beaches in summer. The islands are well known for strong currents and changeable conditions, so dives are always chosen on the day by the skipper according to wind, swell and tide, and a day on the Muirons usually combines two sites with lunch on the boat in the lee of the islands.

Muiron trips leave Exmouth early (around 8:00–8:30 am). Operators collect divers or meet at their shop, then launch from Exmouth Marina (2 km south of town) or Bundegi boat ramp (14 km north). The islands lie about 15 km (9.8 nautical miles) north-east of the tip of North West Cape; the run takes roughly 1 hour from the marina and less from Bundegi, and it can be bumpy in a south-westerly.

Sites have public moorings; the boat ties off and divers giant-stride from the stern. Full-day double-dive trips with lunch on board.

The Muirons are exposed: the crossing and the western sides take the brunt of south to south-westerly winds and swell, and the afternoon sea breeze (often 15–25 knots, especially October–March) makes the return trip rough, so trips run early and are frequently cancelled for wind. Strong tidal currents run between and around the islands; drift sites such as The Gap are timed with the tide, and building swell often limits which side of South Muiron is diveable. Visibility 5–20 m, lower during plankton blooms and after the March–April coral spawn.

Cyclone season November–April. DBCA advises carrying a PLB because conditions can change quickly.

Descend quickly with the group and drift with the tide over the sponge garden at 14–18 m, staying near the bottom. Deploy a DSMB on the guide's signal and drift through the safety stop for boat pickup.

Dive Ningaloo paused all Muiron Islands diving from 21 August 2025 after the coral bleaching event (replaced with Westside trips); Exmouth Dive & Whalesharks Ningaloo (Exmouth Diving Centre) runs Muiron dive and snorkel day trips when weather allows; Ningaloo Whaleshark Swim and Ningaloo Whaleshark-N-Dive offer Muiron dives on request. Check current status before booking.