Standing on the crowded corso of Ton Sai Bay last Saturday, it was difficult to see that Thai tourism was in the doldrums. Hordes of visitors—sandals and smartphones held aloft—were making amphibious landings from an armada of tourist boats and marching up the beach. Ton Sai is where daytrippers to Phi Phi Don, the larger isle in the Phi Phi islands group, stop for lunch at a pair of cacophonous, hangar-like restaurants, designed for large numbers of people to feed efficiently on cheap buffets.