Siam Safari is closer to Patong between Patong and Karon and is not as nice as Kok Chang which is south of Kata.
If you want to go to Phi-Phi I strongly recommend an overnight trip as it is at its most beautiful first thing in the morning or before sunset after all the daytrippers have left. You can buy a return ferry trip including transfers from any travel agent locally and there is accomadation to suit all budgets. The beauty of doing this is that you can organise a long tail boat to take you to Maya Bay early in the morning before the crowds and you can go to viewpoint to watch the sunset. This is the only way to really experience the beauty of Phi -phi. Day trips are rushed and you end up at the best places at the busiest time of the day.

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