Although the islands off peninsular Malaysia's west coast, such as Penang and Langkwawi are more well known, the smaller islands off the east coast have their own charms, and depending on the time of year, they can be a better option. Perhaps more importantly, unlike the heavily developed islands of the west, the eastern islands offer a chance of something a little more idyllic.
Among the choices, Tioman Island would be our top pick. It's less developed and more laid back that the other big islands, yet has a good range of accommodation options and is easy to get to.
Since Tioman is a sun and sea destination, you want to go when the weather is at its best. Fortunately, the island has a long dry season which lasts from February to August. November to January are the only months to be avoided.
One of the advantages to Tioman is that you can fly there. Berjaya Air offers flights from both Kuala Lumpur and Singapore. Note that flights from KL are out of Subang airport and not KLIA. The alternative to flying is to make your way overland to Mersing, and then take a ferry from there.
It's really up to you and how much time you want to spend lazing about on a beach. Scuba divers will probably want to give themselves at least three full days to explore the good sites nearby, although there are enough good dive sites to keep you busy for a week or more.
While most of Tioman's accommodations are a bit on the rustic side, there are a few outstanding exceptions. At the top end is the Japamala Resort, occupying its own little patch of jungle at the southern tip of the island. The other reliable option is the Berjaya Resort, which has a golf course and luxury suites. A new option, as yet unchecked by my or any of my collegues, is the Tunamaya Resort, also on the southern end of the island.
Tioman is rather undeveloped, and with the exception of the area around the airport, there are no roads. The only way to get from one place to another is generally by boat.
Tioman is mainly a lie-on-the-beach destination. There are a few scenic waterfals and undeveloped beaches around the island, but the main activity people come here for is snorkeling or scuba diving. Most of the beaches have good reefs which can be reached via a short paddle from the beach, and are good for snorkeling. While the scuba diving is not the most spectacular that the region has to offer, it is good and quite easy as well. Conditions are usually relatively calm and clear, and most of the dive sites are within a 20 minute boat ride from the beach resorts. See our companion SEA Undersea guide to Tioman for more information about the diving.
Lastly, there is a golf course on the island, as part of the Berjaya Resort (see above). The course is open to non-guests, so I'm told. It also appears that you have to watch out for the occasional monkey that might steal your ball.