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Hotels, dive operators, gear, and how to get here are on the Osprey Reef location page.
Overview
The northern point of Osprey Reef, a submerged Coral Sea atoll about 350 km offshore from Cairns and reachable only by liveaboard. A coral shelf at 10–15 m steps down to a natural amphitheatre around 20 m, then the wall drops vertically into more than 1,000 m of open ocean. North Horn is built around its sharks: a controlled feed run here for decades has habituated 20–30 grey reef sharks plus whitetips and silvertips that circle within a few metres of seated divers, while scalloped hammerheads, manta rays and dwarf minke whales pass through in the cooler months. Visibility routinely tops 40 m over walls hung with gorgonians and Acropora gardens.
Briefing note
Advanced certification and recent deep-dive experience are required; depth, blue-water disorientation and currents that can run strong make this an experienced-diver site. Operators run a managed shark feed at North Horn from a fixed bait drum while divers stay seated on the amphitheatre ledge. The reef lies within the Coral Sea Marine Park — no fishing or collecting. Open-ocean crossings are weather-dependent and surface intervals are often rough; nitrox is recommended for repetitive deep dives.
What you'll see
8 species curated- year-roundGrey reef shark
- year-roundWhitetip reef shark
- year-roundSilvertip shark
- rareScalloped hammerheadPeak: Jun · Jul · Aug
- year-roundDogtooth tuna
- year-roundGiant trevally
- year-roundGreen sea turtle
- rareDwarf minke whalePeak: Jun · Jul
Conditions
| Month | Water | Visibility | Current |
|---|---|---|---|
| Jan | 28–29 °C | 25–40 m | moderate |
| Feb | 28–29 °C | 25–40 m | moderate |
| Mar | 28–29 °C | 25–40 m | moderate |
| Apr | 27–28 °C | 30–50 m | mild |
| May | 26–27 °C | 30–50 m | mild |
| Jun | 25–26 °C | 30–45 m | moderate |
| Jul | 24–25 °C | 30–45 m | moderate |
| Aug | 24–25 °C | 30–45 m | moderate |
| Sep | 24–25 °C | 30–50 m | moderate |
| Oct | 25–26 °C | 30–50 m | mild |
| Nov | 26–28 °C | 30–50 m | mild |
| Dec | 27–29 °C | 25–45 m | moderate |
Season calendar
Peak season highlighted · current month outlined
Next step
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