100s and 1000s is one of two additional moored sites in Lighthouse Bay (with Fish Hole) that the Aussie Marine Adventures dive series describes as worth a look beyond the main trio of Blizzard Ridge, Labyrinth and Gulliver's. The name, borrowed from the sugar sprinkles, refers to the clouds of small reef fish over the reef.

Like the rest of the bay it is a shallow ridge reef with a maximum depth of about 14 m, surrounded by sand. That setting concentrates life: dense schools of small fish such as fusiliers, damsels and anthias, predators including trevally and coral trout, turtles, sea snakes, whitetip reef sharks and wobbegongs. Humpback whales are commonly heard during winter and spring.

There is little published detail specific to this site, so treat it as a typical Lighthouse Bay dive: easy depths, generally mild current, suitable for Open Water divers and guided beginners. Operators pick between the moored sites according to wind, tide and which moorings are free.

Coral here was affected by the 2025 marine heatwave.

Planning notes: Open Water certification is recommended and the site is rated beginner. Expect to spend most of the dive around 12 m, with a maximum of about 14 m. Access is by boat only, and site selection depends on wind, swell and tide on the day. Best season: April–November (whale sharks March–July, humpbacks July–October, mantas year-round). Traffic: moderate (occasional charters/club dives).

From Exmouth, charters meet at the operator's shopfront or collect divers from accommodation and either launch at Bundegi boat ramp (about 14 km north of town on Murat Road, sealed, 2WD) or travel from Exmouth Marina (Mortimer Road, 2 km south of town). Lighthouse Bay sits just north of Vlamingh Head Lighthouse at the very tip of North West Cape, roughly 30–45 minutes by boat from Bundegi depending on sea state. Operators run double-dive days with a lunch break on board; sites are on public moorings installed to protect the reef, so the boat ties off and divers giant-stride from the back deck.

Lighthouse Bay is on the northern tip of the Cape and is sheltered from the prevailing south to south-westerly swell that hits the western side, which is why it is the fallback when the west side and Muirons are blown out. It becomes rough in strong northerly or north-easterly winds and in the afternoon south-westerly sea breeze that wraps around the Cape (often 15–25 knots from late spring to autumn), so trips run in the morning. Visibility is 5–20 m, dropping around the March–April coral spawn and during plankton blooms.

Cyclone season runs November to April; trips are cancelled for cyclone warnings. Tidal flow is noticeable around the Cape on springs.

Descend the mooring, circuit the reef at 10–14 m and return to the line for a safety stop.

Dive Ningaloo – double boat dives several days a week, all certification levels including Discover Scuba; Exmouth Dive & Whalesharks Ningaloo – regular Lighthouse Bay trips; Ningaloo Whaleshark Swim (Whalesharks Exmouth) and Ningaloo Whaleshark-N-Dive – Lighthouse Bay dives as weather allows.