Sabah
Kinabalu Park - If kids in your family are experienced hikers, climb Mt. Kinabalu, the highest mountain in Southeast Asia 4,095m (13,445 ft). On the first day, you'll find yourself hiking in the rain forest in rhododendrons and orchids. On the second day, get up early to reach the granite summit by sunrise. From the top, there are incredible views in all directions.
Along the way, you'll see the canivorous pitcher plant (also called Nepenthe). Insects, attracted by a sweet nectar from the plant, check in, but get caught in the sweet ooze inside the plant. An amazing little mini-ecosystem.
After your hike, soak in the restorative waters of Poring Hot Springs. If you're feeling at all energetic, you can visit the butterfly farm (don't miss the caterpillar house and butterfly nursery), canopy walkway or hike to Kipungit waterfall.
Pulau Tiga National Park - The TV program, "Survivor," was filmed at this park, but unlike the show, your family can stay in comfort in a resort hotel and dine on gourmet food on Pulau Tiga. A friend writes, "the staff taught the girls to fish, took them out on their boats and showed them the mud volcanoes."
Tunku Abdul Rahman National Park - Snorkel in clear waters and explore lovely coral reefs teeming with tropical fishes, sea cucumbers, starfish, cowrie shells. White sandy beaches and warm water of Manukan Island are perfect for little kids. Bigger kids will also enjoy hiking on nature trails on Pulau Gaya to look for wild boar and monitor lizards. To get to the islands, take a boat from Kota Kinabalu.