North Twin
Depth is the range from the top of the site to its usual maximum; "recommended cert" is the mainstream-agency level operators usually ask for, not a legal rule. Currents and visibility change daily — treat everything here as planning ranges.
The Twins are a pair of outlying islands toward the archipelago's western edge, and North Twin is the busier sibling: granite boulder fields rolling down to submerged heads where gorgonians grow to armspan and glassfish smoke the gullies. Trevally and mackerel raid from open water, potato-sized nudibranchs decorate the rock, and mantas or a passing whale shark reward boats that linger in the right weeks. The diving is unfussy, big terrain, moderate depths, current enough to keep fish interested, which makes it the itinerary's reliable middle act between the southern tunnels and Black Rock's main event.
The moment you come for: Armspan gorgonians on granite, raiding pelagics, dependable mid-trip quality
Topography: Granite boulder slopes and submerged pinnacles off a small island
Know before you splash
Hazards: Current on the exposed heads and open-water position.
Conservation: Rarely more than one boat present; keep it looking that way on the reef itself.
Nitrox: Worth it here — profiles sit in the range where enriched air meaningfully extends no-stop time (with the training to use it).
Who you'll meet
Common Reef (Day) Octopus
Giant Trevally
Great Barracuda
Lionfish
Nudibranchs
For photographers
Wide angle: ★★★★☆ · Macro: ★★★☆☆ — editors' 1–5 rating of what this site gives each style of shooting