Khao Deang Viewpoint

Kaeo Cave

Sai Cave

Phaya Nakorn Cave

Thung Sam Roi Yot (Bueng Bua) 

Mangrove Swamp Forest Nature Trail

Sam Phraya Beach

Leam Sala Beach

       The topography of Khao Sam Roi Yot National Park is comprised of a karst topography with rocks dating from Permian Period, approximately 28-230 million years ago. The rugged coast is mixed with coastal plains, lagoon beaches, and shallow seas. There are many limestone islands located near the coast, from Khao Kralok in the north to Khao Rang in the south, across a distance of about 30 kilometers. Islands include Ko Kho Ram, Ko Nom Sao, Ko Rawang, Ko Rawing, Ko Sattakood, and Ko Ki Nok.
On the west side of the National Park is a plain area with water throughout the year. Thung Sam Roi Yot, which in the past used to be the sea or bay, but became blocked by mud and sand dunes. As such, the sea receded because of the influence of freshwater from the land, and the lowland area has seen sediments accumulate, and the area gradually become a mix of saltwater and freshwater. Thung Sam Roi Yot's freshwater originates from the Tenasserim Hills, and flows through Poradok Creek, Kamin Creek, Nong Kang Creek, Rai Ta Pueng Creek, and into the sea through Khao Daeng Canal. The average water depth of Thung Sam Roi Yot is 3 meters in depth.

         Khao Sam Roi Yot features karsts with steep slopes made of limestone. It has deep valleys, and the highest summit in the National Park is as high as 605 meters above sea level. The highest mountain summits are Khao Chalong Fang, Khao Krachom, Khao Yai, Khao Tham Prathun, Khao Daeng, Khao Thian, Khao Hup Chan, and Khao Khan Bundai. There are many places in which limestone is found, and limestone helps form caves, such as Kaeo Cave, Sai Cave, and Phraya Nakhon Cave. These have been created by natural erosion or weathering, making caves or grand canyons.
The northern border is adjacent to Khao Lang Lueat in Pran Buri District, and the southern border is next to Kui Nuea Sub-district in Kui Buri District. To the east is the Gulf of Thailand, and the western border is adjacent to Thung Sam Roi Yot in Sam Roi Yot District.

       The weather in the park is influenced by monsoons. There are 3 main seasons. Winter is between October and February is cool and dry, with temperatures between 18 and 25 degrees Celsius.
Summer is between March to May with hotter temperatures around 32 degrees Celsius. In the rainy season, which runs from June to September, the temperature is between 20–30 degrees Celsius. Strong winds and occasional storms during periods of strong winds can cause waves for approximately 3 to 7 days.

      Winter is calm, so the the influence of local winds and waves can be clearly noticed; land winds blow toward the inner shore. The sea breeze blows off the shore at night.
From May to September, the southwest monsoon (local name: Lom Wao) begins, which has little effect on navigation due to the wind blowing off the coast at an average speed of 10-30 kilometers per hour.
From October to December, the southwest monsoon gives way to the northeast monsoon. The wind direction is indeterminate, and the waves are not particularly large.

        Due to the mountainous terrain and varied climate, the ecosystems in Khao Sam Roi Yot National Park are multiple. The areas can be divided into two main characteristics: wetlands and land based:
Plant communities that occur in wetland areas include:
•    Most of the plants are biennial plants such as various types of Umbrella plants, Ground Chestnut, Common Reed, Echinochloa crus-galli (L.) P. Beauv., Southern Cutgrass, Sacred Lotus, various types of Water Lily, Monochria hastata, Elephant Ear, Limnocharis flava (L.) Buchenau, Water Lettuce, Lesser Duckweed, and Leafy Bladderwort.

•    Mangroves Swamp Forest line the banks of Bangpu Canal, Khao Daeng Canal , and Lam Rang Sakha stream branches. Plants are Olive Mangrove, Rhizophora apiculata, Rhizophora mucronata, Excoecaria agallocha, Xylocarpus moluccensis (Lam.) M. Roem, Ceriops tagal (Perr.) C. B. Rob., Navy Bean, Bind-Poll, Garden Quinine, Nypa, and Derris trifoliata Lour. 
Don Ta Kat is an open area that is influenced by saltwater but does not flood. It is home to biennial plants such as Seablite, Pigweed Purslane, Benghal Dayflower, and Teucrium viscidum Blume.
The ecosystem on dry land consists of:
•    Beach forests, which can be found along beaches which do not flood. The ground is made up of sand, gravel, and rocks, and is home to important plants found such as Australian Pine, Portia Tree, Alexandrian Laurel, Blackcurrant, Tropical Almond, Milkey Tree, Atalantia monophylla DC, Seashore Screwpine, and Beach Morning Glory.
•    Most of the mixed deciduous forest is located on limestone hills, and they are home  to plants which gow in specific conditions. These include Dracaena loureiri Gagnep, Kalamet, Easter Tree, Kariyat, and Andaman Satinwood. Perennials found in the area often have stunted stems due to the limestone-based soil and lack of soil texture. The area where there is a lot of organic matter accumulation is  in the valley and the foothills, where plants grow in thick soils. As such they have large stems, but these areas are scattered and small in size. Plants found include Crateva magna, Ebony Tree, Diospyros dictyoneura Hiern, Afzelia Wood, Ivory, Water Jasmine, Willow-Leaved Justicia, and Memecylon ovatum Sm.

        The term "Sam Roi Yot" is used to refer to both a national park and a mountains, but it is also the name of a plant, which is also called Creeping Club Moss. Other plants, such as Dracaena surculosa Lindi and Vine Spike Moss are plants closely related to ferns found throughout Thailand, particularly in the south and east. There are two types of stems: ground-level stems and erect stems that can reach a height of 0.5 meters. These grow in pine forests, and have small leaves. Propagation organs take the form of dangling blisters near the plant's tip, which are called Cones. Sam Roi Yot grows best on sandy soils in hillside plains that receive bright sunlight, and is found on flatlands and on slopes up to 1,000 meters.

        Khao Sam Roi Yot National Park offers a wide variety of wildlife, especially bird species, which at least 316 species of resident and migratory birds. It is one of the few places in Thailand where the Purple Heron nest and breed. Important resident birds include the Lesser Whistling Duck,  Slaty-Breasted rail, White-Browed Crake, and Purple Swamp Hen.
Large mammals are rarely found in Khao Sam Roi Yot National Park, with most being nocturnal or burrowing animals. . Mammals found include Serow, Barking Deer, Lesser Oriental Chevrotain, Wild Boar, Slow Lorises, Long-Tailed Macaque, Dusky Leaf Monkey, Common Palm Civet, Small Asian Mongoose, East Asian Porcupine, bats, Great Bandicoot, Large Buckwheat, Roof Rat, Malayan Horseshoe Bat, and interesting species found in the coastal waters such as the Lrrawaddy Dolphin.
Among the reptiles and amphibians found are Elongated Tortoise, Siamese Box Terrapin, Black Pond Terrapin, Orange-winged Flying Lizard, Oriental Garden Lizard, Blue Crested Lizard, Many-Lined Sun Skink, Common Water Monitor Lizard, Reticulated Python, Monocled Cobra, Malayan Pit-Viper, Indo-Chinese Rat Snake, Golden Tree Snake, Asian Common Toad, Thai Oriental Frog, Asian Grass Frog, Mangrove Frog, Asian Painted Frog, and Green Paddy Frog.

        From the survey and data collection, no less than 45 species of fish and other aquatic animals were found, including Striped Snake Head Fish, Walking Catfish, Nile Tilapia, Minnow, Silver Barb, Swamp Eel, Short-Bodied Mackerel, Indian Mackerel, Diamond-Scaled Gray Mullet, Stingray, Mudskipper, Banana Prawn, Splendid Squid, Green Tidal Crab, Blue Swimming Crab, Apple Snail, Pond Snail, and Green Mussels. There are also many other types of animals such as Common Mormon, Small Grass Yellow, Dragonfly, Chironomids, Rice Grasshopper, Cricket, Red Cotton Bug, and Horseshoe Crab.