Castle

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What you'll see (19)

Whitetip Reef SharkTriaenodon obesusseen 18× near here

Masked BannerfishHeniochus monocerosseen 8× near here

Whitecheek SurgeonfishAcanthurus nigricansseen 6× near here

Sabre SquirrelfishSargocentron spiniferumseen 6× near here

Pacific Bullethead ParrotfishChlorurus spilurusseen 6× near here

Pacific Sailfin TangZebrasoma veliferseen 6× near here

Crescent-tail BigeyePriacanthus hamrurseen 5× near here

Steephead ParrotfishChlorurus microrhinosseen 4× near here

Moorish IdolZanclus cornutusseen 4× near here

Bignose UnicornfishNaso vlamingiiseen 4× near here

Bluefin TrevallyCaranx melampygusseen 4× near here

Golden DamselfishAmblyglyphidodon aureusseen 4× near here

Purple QueenfishMirolabrichthys tukaseen 4× near here

Spotfin LionfishPteropterus antennatusseen 4× near here

SharksuckerEcheneis naucratesseen 3× near here

Sixbar WrasseThalassoma hardwickeseen 3× near here

Grey Reef SharkCarcharhinus amblyrhynchosseen 3× near here

Spotted ParrotfishCetoscarus ocellatusseen 3× near here

Pennant BannerfishHeniochus chrysostomusseen 3× near here

Planning a trip

8–12 days

worth going for

Long haul, usually two flights.

5,003km from Singapore — about 24h each way, so two of those days are travel. 5 dive sites within 25km.

When people dive it

Busiest Apr, Aug, Oct, Nov, Dec · almost nobody dives it May, Sep.

From 724 logged sightings — when divers are in the water, which is not quite the same as when visibility is best.

Dive Crew is a dive group from Singapore. Members plan trips here, log their dives, and share their photos of each site.

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Season

Prime

October is as good as it gets here.

Southern hemisphere, so the calendar inverts: the good months are the ones that are cold at home.

The year here

JFMAMJJASOND

Best here: June, July, August, September, October.

The Great Barrier Reef and Coral Sea — no monsoon here; the season is rain and water temperature. Written by hand from how the season actually runs, calibrated against what the boats do, since a season that disagrees with the operators is wrong however good the meteorology behind it. It describes most years, not this one: the forecast above is what knows about next week.

Moon and tides

Waning gibbous

72% lit · day 20 of the lunar month

Neap tides

Neap tides — the smallest range of the month, so the weakest currents. Easy conditions and usually the clearest water, though a drift site may barely drift.

New 10 Oct Full 26 Oct

Phase computed here, not fetched. This is the spring/neap cycle, which sets how hard the water moves — not a tide table: no free source publishes high and low water for Southeast Asian reefs, and the range peaks a day or two after the moon does, by an amount that varies with the coast. For times on the day, ask the operator.

Getting there

~16h 45m

door to water, each way · 4 legs

FlightCairns (CNS)~9h 12mFlight time plus the airports at both ends. A connection adds to it.Find flights →
Transferthe jetty~5h 3mRoad transfer to the coast, usually arranged by the resort or liveaboard.Directions →
Ferrythe crossing~2hAt this distance the last stretch is a scheduled crossing rather than a dive boat, so book it before the flight — a missed sailing usually costs a day. Which crossing it is has been worked out from the distance and not from a timetable; ask the operator.
Dive boatCastle~30 minThen the dive boat out from the island.

📍 Castle on Google Maps 🧭 Route from Cairns

Times marked ~ are estimated from straight-line distance and will be roughly right at best. The road legs are the ones Google Maps answers properly; it will not plan the ferry or the dive boat at all. A dive site's coordinates put a pin in open water, so the map link drops you on the site, not on a jetty.

Details

Country: Australia
Marks: 13°51.111'S 146°33.803'E
Position: -13.8518, 146.5634

Where it is

Loading the map…

Nearby

Sightings and photographs from iNaturalist contributors, research-grade records within 6km, under Creative Commons licences. Counts are what divers and snorkellers have bothered to log — a common fish with few records is common all the same.