The world-famouns Sepilok Orang Utan Sanctuary near Sandakan is home to orphaned or captured orang utans where they are slowly readapted to the jungle environment.
With a ticket you can enter the park two times a day. So if you buy a ticket in the afternoon you cannot enter the park next day with the same ticket.
The best time to visit is at feeding times (approximately 10am and 3pm) as this is the probably the only chance of seeing the orangutans and other monkeys (such as the long-tailed macaques) which appear for the free feed of bananas and sugar cane. Note that if it is raining, the feeding times may be delayed as the rangers prefer not to sit out in the rain.
Within the reserve, the visitor is restricted to the boardwalks but there are some walking trails through the jungle. The visitor is also restricted to what they can bring into the Centre - small backpacks are permitted, but neither handbags nor water bottles (unless inside your backpack) nor insect repellent are allowed. It is best to go with as little as possible i.e. no bags, backpacks, water bottles. There is a shop selling water and other food items in the carpark.
Since the Centre is situated inside a tropical jungle, you should expect biting insects (spray yourself before you go in as repellent is not permitted inside). Also expect to get rained on. There is no shelter at the viewing area and thus a poncho is a good investment.
Umbrellas aren't really useful as the rain can be absolutely torrential side ways at a relentless pace for over an hour complete with thunder and lightening. Besides umbrellas block views of others. It can be dark inside the jungle with difficult lighting at the viewing area if it is overcast so consider this if you are the avid photographer.
Given the Centre is a popular tourist destination, expect that the morning feeding time will be crowded with a good half to dozen tour buses fresh from the morning flights from Kota Kinabalu. The hundreds of sweaty visitors will keenly jostle for that perfect photo. The afternoon feeding time is possibly a quieter choice for those with the luxury of time with the added delight of seeing a larger number of the animals in a more personal, peaceful atmosphere.