This attraction is actually comprised of two islands:

Ko Rok Nai - This is where the Mu Ko Lanta National Park’s Ranger Station is located. Ko Rok Nai is an island that is mostly steep cliffs. To the east, it offers a beach and unspoiled coral reefs among rocks. Laem Thong and Ao San Chao are to the north. Ko Rok Nai offers white sandy beaches, crystal clear water, and is still very intact. Nature trails are available, where tourists can enjoy the exercise and various species of plants. A camping ground is available. Contact Mu Ko Lanta National Park, Tel. 0 7562 9018 – 9, Fax. 0 7568 4153.
 
Ko Rok Nok - Ko Rok Nok is full of soft white sandy beaches and coral reefs in shallow water in the southeast and the south. Hat Thalu and Ao Man Sai are situated at the end of the island.
To get there: Rent a boat from Pak Meng Pier, which takes about 3 - 4 hours. Alternatively, take the speed boat from Ko Lanta. Contact tour operators, resorts or bungalows on Ko Lanta Yai. 

Remarks: 
- Since Ko Rok is quite far, trips by a long-tail boat is not recommended, especially during bad weather. 
- Admission to the Mu Ko Lanta National Park including Ko Rok : Adult 400 baht, Child 200 baht

- The islands in the area of Mu Ko Lanta National Park, including Ko Ma, Ko Hai, Ko Rok, Kong Hin Daeng - Kong Hin Muang and Ko Ha, are yearly closed from May 16 - October 31.