Bashful Bommie is Calypso Reef Cruises' usual first dive at Opal Reef and one of the best-known sites out of Port Douglas. Diveplanit's detailed profile records a top at 5 m, median depth of 15 m and bottom at 18 m, with the bommie rising around 18 m from sand. What makes it special is that it is double-sided: one face looks onto the sheltered southern reef edge, the other onto a deeper ocean channel facing blue water.

On the channel side the walls are fringed with sea fans at the base and riddled with holes and crevices. This is where the larger fish are: Spanish mackerel and red bass hunt in the deeper water, according to Visit Port Douglas Daintree, and Diveplanit lists barramundi cod, giant sweetlips and pale blue-spotted cod among the residents. Schools of yellowtail fusiliers stream past in the current.

The sheltered side is a coral garden with giant clams and anemonefish, and Scuba IQ highlights the combination of giant clams, incredible corals, a wall and a swim-through. The humphead Maori wrasse that frequents the site is famously friendly – Diveplanit describes it as the friendliest fish – and often follows divers around the bommie. Butterflyfish are abundant, including dot-and-dash, saddled and vagabond species, and sub-adult sailfin snapper are a notable sighting.

The dive profile is easy to manage: start deep on the channel side, then work shallower on the sheltered side, finishing on the shallow reef top. The contrast between the two environments means small reef fish and larger pelagic visitors can be seen on the same dive. Visibility is usually 15–30 m.

The site suits all levels, and snorkellers can enjoy the garden side. It is a great introduction to Opal Reef and a favourite of photographers for the Maori wrasse encounters.

Boats to Opal Reef leave Crystalbrook Superyacht Marina on Wharf Street, Port Douglas; Calypso Reef Cruises checks in around 8:15 am for a 9:00 am departure and returns about 4:30 pm, and Wavelength and Scuba IQ/Blue Dive leave around 8:00 am. Park in the marina car park or on surrounding streets (free all-day parking along Wharf/Dixie streets), or use the operators' courtesy pick-ups from Port Douglas and the northern beaches. Opal is about 60 km north-east of Port Douglas; the crossing takes 80–90 minutes, part of it threading through the protected Tongue Reef maze.

Divers gear up on board and enter by giant stride at a mooring; on Calypso some sites are reached by tender from the main vessel. The skipper chooses three sites on the day depending on wind and tide.

Opal is a crescent-shaped outer reef near the continental shelf edge. Its shape gives some shelter from the south-east trades that blow from about April to September, so several moorings (Bashful, Sno, Blue Buoy) stay diveable in 15–20 knots, but a 25-knot-plus trade wind makes the crossing rough and operators may cancel. Exposed sites on the seaward face and in the channels between North, Middle and South Opal are dived only in light winds and suitable tides.

October–December is typically calmest with the best visibility; the wet season (December–April) brings northerlies, storms, cyclone risk and marine stingers (November–May). Tidal currents run through the gaps between the Opal reef sections and around bommies, strongest on spring tides – channel and bommie sites are timed for neaps or slack water.

Descend to the base of the bommie at about 18 m on the channel side, follow the fan-fringed wall looking into the blue for mackerel and red bass, then swing round to the sheltered side and work up through the swim-through and coral gardens. Safety stop on the 5 m reef top.

Calypso Reef Cruises – daily Opal trips (3 dives/snorkel sites); Wavelength Reef Cruises – snorkel-only daily trips to exclusive Opal moorings; Scuba IQ / Blue Dive and Tech Dive Academy – small-group dive days several times a week; private charters.