Ko Nang Yuan
Ko Nang Yuan is a small island very close to Ko Tao. It is famous for its diving spots and its great snorkeling beach. Many day trippers come from the islands of Ko Tao, Ko Pha Ngan and Ko Samui, as well as from Surat Thani and Chumphon on the Thai mainland.
By Air & Ferry
The fastest connection to Koh Nang Yuan from Bangkok is via air to Chumphon Airport then a high speed catamaran to the island. Chumphon Airport is located 30km north of Chumphon town in Pathio District (alternative spelling Pathiu). It has direct multiple daily flights connections with Bangkok's Don Muang Airport. Nok Air operates 3 daily flights between Bangkok (Don Muang, DMK) and Chumphon Airport, Pathio District, Chumphon (CJM).
Nok Air offers daily flight+minivan services from Bangkok to Koh Nang Yuan v.v. by flying with Nok Air from Bangkok to Chumporn and transferred on a ferry to Ko Nang Yuan. This can be booked directly from their website.
Services at the Airport. The airport has transit agents for onward travel to Chumphon and the island. Lomprayah has a counter at the airport offering direct connections to the pier for High Speed Catamaran transfer services between to Koh Nang Yuan and onto Koh Tao and Koh Phangan.
By boat from other islands in Chumphon Archipelago
There are two types of boat available:
Long boat taxi from Ko Tao. This is likely to set you back 100 baht each way, though it may be possible to get a return trip for 100 baht total. Snorkeling day trips from Ko Tao start at 250 baht, including round trip boat fare.
It is also possible to come here for a snorkeling day trip from Ko Samui for about 1200 baht, though this is questionable value considering that whilst the trip may take the whole day you are likely to spend only an hour here. If you are really interested in visiting here stay at least one night on Ko Tao.
Note that visitors to Ko Nang Yuan island must pay a 100 baht fee (waived if you stay on the island).
Note also that plastic bottles and cans are banned from the island. As water and other drinks in glass bottles cannot be purchased in Ko Tao (note: yes, they can, try any 7-11) it effectively means that liquid refreshments must be purchased at the restaurant on the island (at wildly inflated prices).
The island is tiny; the only way to get around is by walking.
Snorkeling and diving
Island to Island Zip Line
Koh Nangyuan and Goodtime Adventures have teamed up to bring you the worlds only zip line between islands! There are limited places with a new group every hour from 09.00-16.00. You can make your own way to the island and sign up for these times (operating on a first come first served basis) or you can book with Goodtime Adventures  +66(0)872753604 on Koh Tao for a dedicated trip or half day adventure trip that includes the zip line as well as a nice view point walk, guided snorkeling of Koh Nangyuan's famous reefs and time to enjoy its beautiful beaches. A must do experience!
There is only one restaurant which is part of the Nang Yuan resort. It has a selection of Thai and Western food. One of the best dishes on the menu is the BBQ fish.
Note that the restaurant takes full advantage of its monopoly status on the island. Prices for food are 3-4 times what you will pay on Ko Tao, and the wait staff makes it clear that they are doing you a favour by serving you. If you stay on the island for lunch it is likely to be cheaper (and the food is better) to get a return boat taxi to Ko Tao and have lunch there.
The only accommodation on the island is the Nang Yuan Diving Resort . The island is very beautiful and is well worth it if you really want to "get away from it all". A few things to consider if you want to stay here though:
Currents can be very strong.