The names translate literally from Thai as 'Grandpa Rock' (Hin Ta) and 'Grandma Rock' (Hin Yai).
The rocks are composed of granite, which has eroded into unique, smooth contours over geological timescales.
The site remains a popular destination for both domestic Thai tourists and international visitors due to the rocks' natural resemblance to human anatomy.
The geological process responsible for the formation involves differential weathering along joint planes in the granite bedrock.
Hin Ta and Hin Yai are granite rock formations located on the southern coast of Koh Samui, known for their suggestive shapes resembling male and female genitalia. These natural sculptures were formed through long-term weathering and erosion of coastal rock. The site is situated on a rocky headland between Lamai and Hua Thanon beaches. It is a major local landmark often included in island sightseeing tours. The surrounding area features a network of paved paths and stairs leading to the rocks and nearby tide pools. Local vendors operate within the immediate vicinity, selling snacks and souvenirs. The formations are accessible via a short walkway from the main parking area.
From the raised wooden viewing platform, which provides the best angle to capture both the Hin Ta and Hin Yai formations in a single frame.
Wear footwear with good grip, as the granite rocks can be slippery and uneven when wet or near the water line.
Combine this visit with a stop at nearby Lamai Beach to optimize your time on the southern part of the island.
Visit during low tide to safely access more of the shoreline and explore the smaller rock pools surrounding the main formations.
Avoid purchasing overly expensive souvenirs from vendors immediately at the entrance, as similar items are available at lower prices in local markets.
Respectful behavior is expected; avoid climbing on fragile parts of the rocks that are restricted to prevent damage.
