Diving and snorkelling
The best dive sites are the seamounts off the southern coast to the island of Ko Kood, the best site being at Ko Wai where there is intensely colourful coral reefs, with depths of five to 18 metres. During the rainy season visibility can be poor and the best time to visit is from November to April. There are many dive centres offering specialising in PADI certificates on most of the main beaches. Prices range from $70-$280 per person. There is no snorkelling to speak of in Ko Chang itself, but the outer islands can easily be reached by boat.
There are a series of scenic waterfalls across the island. It costs 200 baht to enter the national parks. On the east coast the Nam Tok Mayom waterfall has three waterfalls and can be climbed in under an hour. A smaller waterfall at Nam Tok Klong Phu on the west coast can be reached via Khlong Prao. There are plunge pools to cool yourself off after the trek to the falls. There are other, less impressive falls in Khlong Son, White Sands Beach and Kai Bae.
Elephant trekking and walking
On Khlong Prao, Chang Chutiman offer elephant safaris into the interior for 150 baht for half and hour and 500 baht for an hour. Or, if you prefer to do it on foot, you can take a hike yourself. The best place to start is from the southern end of the island. But be warned, it is advisable to hire a local guide!
Sail amongst the islands of Ko Chang between November and March, when you can count on steady winds of 15-30 knots. This time of the year there is the most agreeable climate too.