East Malaysia, also known as Malaysian Borneo, shares the island of Borneo with Indonesia and Brunei and is trumpeted as a land of sophisticated and dynamic cities, pristine rainforests, and magnificent cave systems—not to mention plenteous oil and gas reserves. Intrepid travelers have long lauded Borneo adventure travel as some of the best in the world. Two Malaysian states, Sabah and Sarawak, and the federal territory of Labuan make up about a quarter of the island’s land mass, and while less populated and less developed than its West Malaysia counterpart, Malaysian Borneo is striking in its natural wonders and rich biodiversity.

The adventurous traveler will vie for a chance to encounter the region’s spectacular bat caves and impressive cave systems, including the UNESCO World Heritage Site of Gunung Mulu National Park, where the largest known cave chamber and longest underground river in the world exist. The waters off of Malaysian Borneo are also legendary and offer dozens of dive sites ripe with some of the most impressive coral and marine life – Borneo adventure travel at its best. The petroleum hub of Miri is known for its exotic coral reefs and myriad of flora and fauna, while the various islands off the coast provide excellent jungle trekking opportunities. If you are lucky, you may even catch the elusive native bird, the chicken-like megapode, resounding its cat-like call.

From Kuching, the island’s most advanced metropolis and a lively foodie destination, venture to one of the oldest rainforests in the world—approximately 140 million years in age and home to 221 species of mammals, 420 species of birds, 3,000 species of trees, and about 15,000 species of flowers. The quintessential Borneo adventure travel experiences exist in these lowland and mountain rain forests: play with orangutans and proboscis monkeys at primate sanctuaries; take a river safari to spot endemic killer crocodiles, Bornean clouded leopards, and dayak fruit bats in the wild; and hunt for the Rafflesia, the world’s largest flower.