This group of three islands in the eastern Gulf of Thailand are protected as part of the Khao Laem Ya Ko Samet National Marine Park, but as on Ko Samet this has not prevented development of tourist resorts on two of the three. One island, Ko Man Nai, has been set aside as a sanctuary and breeding center for several species of sea turtles, and does not have accommodations for overnight stays. The other two, Ko Man Klang and Ko Man Nok, have nice isolated beaches and well preserved coral reefs. The island group lies about 5 kms offshore from Laem Mae Phim, which is about 30 kms east of Rayong City, and can be reached by boat in about 45 minutes. Resorts on the two islands rent equipment for snorkeling, sailing, and canoeing.
Hat Mae Ramphung
Located about five km west of Ban Phe this ten km long, somewhat narrow beach is bordered by a road lined with bungalows and resorts, especially at the eastern end where the fishing village of Ban Kon Ao is located. The beach is part of the Khao Laem Ya - Ko Samet National Park and the Park headquarters is on the headland near the village. Entry to the Park costs 20 baht. There are some hiking trails, but the highest point of the headland is reserved for the Thai military. Generally, the beach is cleaner and less crowded toward the western end. Most of the accommodations are in the mid-price range, and there is the usual assortment of breezy seaside eateries and souvenir shops.
Laem Charoen & Hat Sang Chan
These two connected beaches are 5 kms immediately south of Rayong City, separated from the mainland by the Rayong River which passes through the provincial capital then turns east before emptying in the Gulf of Thailand. Lined with bungalows and seafood restaurants, they lack the secluded charm and fresh air of some other beaches in coastal Rayong. On the mainland side the view is back toward the busy port where there are factories producing pungently fragrant fish sauce. The two beaches have an authentic Thai flavor but may be less desirable destinations for those seeking peace and quiet.
Ko Saket Petch
Located just 15 minutes by boat from Hat Sai Thong and the Mataphut Industrial Park, Ka Saket Petch has a good view of the refineries and deep sea port west of Rayong City. Accomodations and other facilities are minimal. While there are beaches and coral formations, superior ones can be more conveniently enjoyed on islands further east and south such as Ko Samet or Ko Chang.
Hat Phayun & Hat Phala
These two peaceful beaches can be a little difficult to get to and are popular with tourists who rent small houses or apartments by the month. The two rather average beaches are connected, and there are some upscale resorts along the 5 km stretch of sand. For those seeking a slower pace of beach vacation, especially those with plenty of time and little interest in entertainment, nightlife and other distractions, Hat Phayun and Hat Phala might be an interesting choice. The beaches are located about 30 km west of Rayong City and can be reached by getting a bus to Ban Chang and then taking a sonthaew (converted pickup truck) to Hat Phayun.
Laem Mae Phim
A long shady beach with accommodations favored by Thai vacationers on a budget, Laem Mae Phim is located about 15 km east of Ban Phe. The bungalows and guesthouses are clustered near the village at the east end of the beach, where there are also seafood restaurants, a dive shop and souvenir shops. The beach is better and less crowded toward the western end, especially on weekends when the section near the village tends to fill up with locals and day trippers from Bangkok. Snorkeling gear, inner tubes, beach chairs and umbrellas can all be rented from local vendors. Boats for day trips to see the sea turtles on nearby Ko Man Nai and Ko Thalu islands can be hired in the village.
Khao Laem Ya - Ko Samet National Park
This National Park includes Ko Samet island and a small section of mainland Rayong east of the provincial capital, and the surrounding waters. Designated a National Maritime Park since 1981, development of tourism facilities both on the mainland and the island has nevertheless proceeded, and the efforts of the Royal Forest Department to control growth have been largely ineffective. In spite of winning a decisive legal victory in 1996 the Department has yet to close down many of bungalow resorts operating in the Park.
Covering 131 sq. km, the Park has some of the best beaches and cleanest, most transparent waters in the Gulf of Thailand. On Ko Samet, which is the main attraction of the Park, there are a few unusual mammal and reptile species (including some snakes), and more than 20 species of tropical birds.
The coral formations around Samet and the several tiny islands nearby are great for snorkeling, but experienced scuba divers may want to seek more challenging reefs, as the ones in the Park are in relatively shallow water.
Article Source: http://www.thailand.com/travel/beach/beach_rayong.htm