A tiny coral islet encircled by powder-soft sand, Lankayan forms a tear-drop of green amid a sea of dazzling turquoise water. The location is one of the finest in the region for diving, famed above all for its frequent whale shark sightings. It’s a perfect place to do a PADI Open Water course, or simply snorkel and laze on the verandah of your chalet. Colourful corals and encounters with Hawksbill turtles are never more than a few flipper kicks away at this slice of paradise.

Since it opened in 1964, the world-famous Orangutan Rehabilitation Centre at Sepilok in northern Sabah has cared for apes orphaned or injured by forest clearance. In 43 square-kilometres of tropical forest they are able to roam wild, re-learning essential survival skills such as climbing and foraging which may have been lost through the trauma of displacement. The hope is that in time the animals will be ready to be sufficiently skilled to be released back into the wild. At any given time, between 60 and 80 adults are present here, along with 25 or more babies and youngsters in the site’s nurseries. A smaller centre for rescued sun bears is an added attraction.

Olive green or chocolatey brown depending on the season, the Kinabatangan is Sabah’s longest river, rising in the mountains of the interior and flowing into the Sulawesi Sea on Borneo’s northeast coast. The mangroves, grassy swamplands, lakes, dipterocarp and ficus forests carpeting its floodplain host a prodigious quantity of wildlife. Safaris are generally conducted in electric-powered longboats. The guides we use in the area are highly skilled and able to identify lesser visited zones along tributaries of the Lower Kinabatangan where you can expect to encounter fewer visitors and more wildlife.

The largest area of protected lowland rainforest in Borneo extends over 272 square miles (438 sq-km) of the Danum Valley in eastern Sabah. Comprising mostly dipterocarp jungle, the area provides sanctuary for an exceptionally rich array of species, from the rarely sighted clouded leopard and Sumatran rhinoceros to more common pygmy elephants, gibbons and proboscis monkeys. Orangutans are also present here. Among the best places to see them is the forest in the immediate vicinity of the lodge where you’ll be staying.

Your first foray into the conservation area will probably be a 107-metre-long canopy walk, from which vantage point you’ll be able to begin ticking off many of the 320 species of birds resident in the valley. Around 30 miles (50km) of marked trails thread through the reserve to observation posts and other places of interest, such as a Kadazan–Dunsum cliff-coffin burial site and Sungai Purut waterfalls. Tubing, night hikes to spot nocturnal animals, and pre-dawn treks to panoramic viewpoints where you can watch the sunrise over the mist-drenched rainforest canopy are also on offer.

Gaya is a mere 15-minute speedboat ride from Kota Kinabalu. Most of its chalets are high up in the jungle canopy, so expect a strenuous climb to reach your room – and not to want to leave once you reach it. The uninterrupted views over the treetops and out to sea from the private balconies are serene, though you’ll doubtless be eager to get into the waves to sample the riches underwater. No matter where in the world you’ve snorkelled or dived, you’ll be blown away by the kaleidoscopic shoals of fish in Gaya’s shallow bay.