Coral Bay is a small beach resort in Western Australia, renowned for Ningaloo reef. Ningaloo is a 300-km fringing reef, which hereabouts lies about 1 km offshore, enclosing the placid lagoon of "Bill's Bay". The resort is family-oriented and has a noise curfew. Serious rowdiness, drunkenness or similar misconduct will get the offender run out of town.
If snorkelling or swimming from the shore, stay in the "green zone" of Bill's Bay. For the best coral formations walk around the headland and then south for 200-500 m, you can then enter the water and drift-snorkel back to the bay. Further south you risk boat traffic, and north end of the bay (called "Skeleton Beach") is exposed to the winds and gets choppy. In spring this north end is also a nursery for reef sharks, which cluster very close to shore. You're permitted to wade, swim or snorkel with them, but occasionally people get nipped, and the sharks are probably best admired from shore.
Snorkelling or diving from a boat is where you really see why Ningaloo Reef ranks as a world heritage site. The quality, variety and quantity of coral and marine life is impressive: turtles, dolphins, mantas and reef sharks are common. The sheltered lagoon enables hard coral to thrive in shallow water close to shore, whereas on most shores (without a barrier reef) wave action wrecks anything shallow and only soft pliable species survive. There is little evidence here (as of Nov 2017) of the common scourges of other famous reefs (such as GBR): bleaching, human damage, trash, or invasive species.
The Ningaloo Reef is also famous for the whale sharks which congregate here from late March to July each year. They're on many people's bucket list and tour places are restricted, so book early and expect to pay over $400 per person for these trips. Spotter planes guide the boats to whale sharks that are close to surface and appear suitable for encounter.