There is definitely some sort of price-fixing cartel on Railay. All the tours and climbing courses are the same price no matter where you go. Restaurants differ by less than 10%, supermarkets are all the same. Hotels and everything is much more expensive than on the mainland, even considering everything has to be shipped in by longtail boat. But who's complaining when we sleep the whole family for 65 euros a night and in Madrid it's freezing cold?
Went on the "five island tour" on a longtail boat. Felt a bit queasy at the beginning - we were on virtually the same tour 9 years ago when we got hit by the tsunami. Also yesterday was full moon. After the first beach I was feeling safer - we had improved on the last tour.
Considering one "island" is Railay (which is actually connected to the mainland, only not by road) and two other stops are actually the same island on different sides this is quite a stretch of the word five. But that is pure Westerner thinking. The Thais were perfectly happy explaining all this the day before. The thing is if you know what you pay for (it doesn't take much brainpower or travel experience to realise the places will be pretty crowded as all tours do the same route) you won't be disappointed. Who cares if it's 5 or 3 islands? We had a great time on the beaches, snorkeling and eating lunch in the shade. The pace was slow, the kids were happy, my bowels stayed put and we didn't see a hint of a tsunami.