Koh Miang is famed for two bays (Honeymoon & Princess), where the King of Thailand's daughter spent her honeymoon. The Island hosts the national park headquarters as well as accommodation options for the Similan Islands, and one can find easy trails for forest walks to viewpoints. And - of course - there is marvelous snorkeling and shallow diving.
The entry to this area is 500 THB / Adult, which have to be paid cash to the Park Rangers. There are different rates for Thai nationals, foreigners, adults and kids.
Please note: In some areas additional park fees have to be payed cash to the Park Ranger. Due to the double pricing system it might be different for nationals and non-nationals.