Lake Barrine is the largest of the natural volcanic lakes on the Atherton Tablelands, a rainforest-fringed crater about 1 km across with a shoreline of nearly 4.5 km, an average depth of about 35 m and a maximum of about 65 m. It formed more than 17,000 years ago in a volcanic explosion, and like nearby Lake Eacham it is fed only by rainfall, with no streams flowing in or out, which keeps the water clear. It sits at about 730 m above sea level within Crater Lakes National Park and the Wet Tropics World Heritage Area.

The lake is better known to tourists than to divers: a pre-war teahouse, built in 1926, overlooks the water and runs cruises, and walking tracks lead to a pair of giant bull kauri trees. Swimming is allowed, and Queensland Parks states that recreational diving is permitted in the Crater Lakes, with commercial diving subject to permit. In practice Lake Barrine is dived far less than Lake Eacham, which has easier entry and a well-known dive route, and there is little published information about diving here.

Expect a similar environment: steep crater walls falling into deep, dark water, fallen rainforest timber along the shoreline, silt on the bottom, visibility typically 5-10 m, and freshwater life such as turtles, eels and small fish. Divers should take the same precautions as at Eacham: altitude-adjusted computers, careful weighting and finning, and awareness of boat traffic from the cruise vessel. It suits Open Water divers wanting to explore a quieter crater lake.

From Cairns drive south to Gordonvale and up the Gillies Range Road (Gillies Highway); Lake Barrine is signposted just off the highway before Yungaburra, about 1 hour from Cairns. Park at the day-use area beside the 1926 teahouse, which also runs lake cruises. The carry to the water is short.

Enter from the shore away from the cruise-boat jetty, and keep clear of the cruise boat's route. There is no dive shop at the lake; the nearest air fills are in Cairns. Lake Eacham, a few kilometres away, has easier dedicated entry and is dived far more often.

There is no swell or current; the lakes are diveable year-round. Visibility is typically 5-10 m and is best in the drier, cooler months (May-October); heavy wet-season rain and algal growth in warm months can reduce it. Surface water is about 23-27 °C, but it is cooler at depth below the thermocline.

Weekends and school holidays bring crowds of swimmers, so dive early. The lakes are at altitude, so adjust your computer or tables and allow time to acclimatise after driving up from the coast; do not dive and then drive back down over the Gillies or Kuranda ranges without a sufficient surface interval. The teahouse cruise boat operates on the lake during the day.

Enter from the shore near the day-use area away from the jetty, check your weighting for fresh water, and follow the shoreline along the fallen timber at 5-15 m, turning at half gas and returning the same way. Tow a surface float so the cruise boat can see you.

Altitude dive: use altitude-adjusted tables or computer; deep water (to about 65 m) close to shore on the crater walls – plan depth carefully.

No commercial operator – occasionally dived independently or by club groups; commercial diving requires a Queensland Parks permit; Cairns and Tablelands dive clubs occasionally organise altitude-diving trips to the crater lakes