Twin Peaks is the best-known dive on Saxon Reef, and Divernet, drawing on Divers Den's Master Reef Guide, rates it among the best dive and snorkel sites on the Great Barrier Reef. Divers Den calls it an unusually varied site: the dive circles two coral bommies with a narrow swim-through between them, and a large tree trunk, carried out from the mainland rivers in some past flood, is wedged between the peaks, an odd and memorable landmark on an outer reef. Beyond the peaks are sandy bays, and the edges of the seagrass that grows in them are one of the few places off Cairns where pygmy seahorses are sometimes found.

Moray eels live in holes near the mooring blocks and are often the first animals divers see. The peaks attract reef sharks, trevally and large cod, according to Divernet, and Tusa Reef Tours adds band fusiliers, humbug damsels and numerous nudibranchs. The coral on the bommies is healthy and varied, with calm lagoons nearby for snorkellers.

Saxon itself is a small reef, about 1.9 km², sitting between Norman and Hastings; Down Under Cruise & Dive describes it as a haven of marine life and thriving coral colonies, and Dive the World notes it is less crowded than its neighbours, with coral and fish that have not grown wary of bubbles. The tidal current can be swift at Twin Peaks, which keeps the fish active but means divers should follow the guide's timing. It suits all levels in calm conditions, and the swim-through and tree trunk make it a favourite with photographers.

Boat access only. Cairns day boats leave from the Reef Fleet Terminal (1 Spence Street) and the neighbouring Marlin Marina on the city waterfront, with check-in between about 7:00 and 8:00 am; most operators run transfers from city and northern-beaches accommodation, and there is paid parking near the terminal. The run of about 55 km out through Trinity Inlet and across the lagoon to Saxon Reef takes around 75 minutes on a fast catamaran and noticeably longer on slower dive boats or into a south-easterly chop.

Twin Peaks is a regular mooring for Divers Den, Tusa Reef Tours and other northern-reef operators. Enter from the stern platform; moray eels live in holes near the mooring blocks.

The prevailing south-east trade winds (typically 15-25 knots from April to September) are what limit Cairns outer-reef diving: above about 25 knots trips may be cancelled, and exposed eastern moorings are used only in light winds. Summer northerlies are gentler but make north-facing moorings choppy. Box jellyfish and Irukandji are present from about November to May (stinger suits on every dive), and the cyclone season runs November to April, when a system in the Coral Sea can close the reef for days.

Visibility drops after heavy rain and strong winds; spring is usually calmest and clearest. Saxon's western lagoons are sheltered; its weather side is dived only in calm conditions. Divers Den warns that the tidal current at Twin Peaks can sometimes be swift, so the site is best dived near slack water or on neap tides.

Descend the mooring, check the mooring blocks for moray eels, then circle the first peak and pass through the narrow swim-through beside the wedged tree trunk. Circle the second peak and explore the sandy bays beyond before returning; check the seagrass edges for pygmy seahorses. Safety stop on a peak top at 5 m.

Divers Den (Reef Quest day boat and Ocean Quest liveaboard) – regular; Reef Experience – daily day trips; Down Under Cruise & Dive (Evolution) – regular; Tusa Reef Tours – Twin Peaks; Aqua Quest and Reef Encounter (liveaboard) – regular