The Phi Phi Islands in Thailand are absolutely gorgeous... rivaling Santorini for the most beautiful place I've been to date. Phi Phi is made up of two separate islands, Ko Phi Phi Don and Ko Phi Phi Le. Often times, the islands are thought of as one, since they are both tiny and are very close together.
The island that you'd stay on is Ko Phi Phi Don, but when talking about this island, it's typically just referred to as "Ko Phi Phi," which is pronounced "ko pee pee." It's about a 1 x 2 mile island in size, with no roads or cars on the island. You get around by long tail boats which are super old fashion (like a lot of the island) and part of the magic of the island's beauty. You can get to the Phi Phi Islands on a ~2 hour ferry ride from either Krabi or Phuket.
You can rent a long tail boat for pretty cheap to take you anywhere on the island. We stayed on the eastern side of the island, relatively close to the port in theory but on the complete opposite side of the island. To get there, it took about 20-30 minutes by boat and was a beautiful ride! The eastern side of the island is much more quiet and relaxing, as the west (near the port) is known to be the party side. It's a lot of fun, but you'll also find a lot of college aged tourists raging here. If you want to party one day, check out Bob's Sailing Booze Cruise. This side, however, is very overcrowded and kind of dirty in my opinion. So, as this trip was a leg of our honeymoon, we were happy to stay on the quiet side and take in the island's beauty. It's a much different world than the port area - clean blue water and a white sand paradise. Regardless of where you stay, it's very easy to get around