From our hotel in Bang Niang (Khao Lak) it took just over 3 hours to get to Tachai, roughly half of it by road, the other half by speedboat. The boat was full to capacity, as has been our experience with most of these seafaring outings, and on arrival, we found the place very crowded. Not sure if being a Sunday affected that, but we were slightly surprised that of the 28 or so passengers, only 2 couples were European, the rest Thai.
The fairly thin strip of beach is composed of beautifully fine white sand, but the area cannot be said to be particularly scenic. To appreciate the snorkelling, you have to get at least 50 metres from the beach because boats churn up the sand, preventing visibility. A second dive area in a sheltered spot is much clearer and there are plenty of fish to see. Lunch was adequate, but no more. A nature trail parallels the beach and gives you the opportunity of seeing some chicken crabs, snakes (!) and hermit crabs.
Although the sea was no worse than moderate, fully 25% of the passengers were sick, and judging by the facial expressions and heads buried in towels, most people considered the boat journey a test of endurance. Anyone with a back problem would have been in real trouble, from the jarring as the keel slammed at high speed into the waves.