Asho's Gap is Coral Bay's signature scuba dive and, according to the Aussie Marine Adventures series, a must-do for any diver visiting the town. The site is a coral outcrop on a sandy bottom at about 12 m that operates as a cleaning station for grey reef sharks. The sharks hover in the current while cleaner wrasse work over their bodies and even clean their teeth, and several sharks may circle at once.

The dive is about sitting still and watching. Divers settle on the sand a short distance from the outcrop and let the sharks come to them; the more motionless the group, the closer the sharks approach. Travel reports describe five or more grey reefs at a time, with blue-spotted rays on the sand and a large school of barracuda overhead. Other regulars include parrotfish, trevally, eagle rays, wobbegongs, nurse sharks and turtles.

The presence of sharks depends on current, and it is one of the few Coral Bay dives where water movement is desirable. Depths are modest, making it suitable for Open Water divers who can hold still and control their buoyancy near the bottom.

About Coral Bay: the town is a small resort settlement on Bill's Bay at the southern end of the Ningaloo Coast, about 150 km south of Exmouth. The outer reef lies close to shore, so both lagoon snorkels and outer-reef dives are short boat rides away, and Coral Bay is home to Western Australia's largest resident population of reef manta rays, seen year-round. Much of the water around town lies within the Maud Sanctuary Zone, where fishing and collecting are prohibited. Advanced divers favour the 'cuts', where open-ocean water funnels through gaps in the reef and brings in sharks, mantas and pelagics, while the calm lagoon suits training and beginners. The 2025 marine heatwave affected northern and central Ningaloo most; southern areas including Coral Bay sustained less damage, according to AIMS.

Coral Bay is 150 km south of Exmouth (about 1 hr 45 min) and 1,145 km north of Perth via the North West Coastal Highway and Minilya–Exmouth Road; Learmonth airport (Exmouth) is the nearest airport. Dive and snorkel tours meet in town (Ningaloo Reef Dive meets at 8:00 am) and transfer by minibus to the Coral Bay boat ramp, about 2 km south of town via Banksia Avenue, or load from the beach. Most dive sites are within a few kilometres — 10–30 minutes by boat — either inside the lagoon, at the passages ('cuts') through the reef, or on the outer reef north of town towards Point Maud and Bateman Bay.

Coral Bay's lagoon is protected by the outer reef and faces north-west, so it stays calm in the prevailing south to south-westerly winds that close exposed coasts; the outer-reef and passage sites, however, need low swell and light winds. The afternoon south-westerly sea breeze (often 15–25 knots in spring and summer) chops up the outer sites, so dives run in the morning. Tidal flow through the passages can be strong on springs.

Visibility is usually 10–20 m, lower after the March coral spawn (in March 2022 a spawn-related low-oxygen event killed fish and coral in Bill's Bay). Cyclone season November–April; stingers possible in warm months.

Descend onto the sand beside the coral outcrop at 10–12 m and settle low and still a respectful distance from the cleaning station. Watch the grey reef sharks come in to be cleaned; avoid rising into their path. After 20–30 minutes explore the surrounding outcrops and ascend to the boat for a safety stop.

Ningaloo Reef Dive & Snorkel – two dives daily on the 'Bay Escape' (up to 16 divers), plus full- and half-day Adventure and Manta Ray tours combining divers and snorkellers; Coral Bay Eco Tours and Ningaloo Marine Interactions/Coral Bay Eco Safaris – snorkel, manta and whale shark tours.