The big trip for Phi Phi Don is the boat trips around the smaller islands. You can go with a tour group, but then you'll be on a fixed schedule and rushed from place to place. I hired a long-tail boat instead and did a full day private tour. It's better that way, paying the extra (around 3000 baht a boat) gets a schedule fitted to you. If you want to spend longer at some places, you can, and move on when you're ready.
Boats are equipped with snorkels and life jackets, so you don't need your own equipment.
If you want a more scheduled package, our friends over at Indo Thai Tours have a range of Ko Phi Phi trips available.
The long tail boat captain took us off to Phi Phi Lei, to kick off with. This is the most overrated of the Phi Phi islands! As we approached a line of speedboats from Phuket direction headed to Maya Bay for the day.
Maya Bay, the bay from the movie "The Beach", is the local tourist trap. It's the main attraction at Phi Phi Lei island. This is sort of a must, but Maya Bay itself gets crowded with tourists, the beach gets packed and the bay fills with boats. The actual beach is a disappointment. It's expensive to land on, and filled with Phuket day trippers!
If you head back into the nature reserve, things get better, there's a tidal pool to enjoy which empties completely at low tide, and a view onto Losama Bay. My boat took me round there to swim and snorkel in Losama later.
I was getting hungry, so back to the main island, to Phi Phi Relax Resort, a quiet resort accessible only by boat. Here the food is cheap and fresh and fast, so a lot of the boat captains come here.
We headed north after this, time for lunch to settle and then more snorkeling. I'm terrible with the underwater camera, the camera shy fish just will not pose properly! But it isn't difficult to photograph these guys. They nibble at your toes if you stop moving, not shy at all!.
After that it was onto a tourist sandy beach, the boat captain asked if there was anywhere else I wanted to visit. The tide was still too low to drop me off at the hotel, I would have to walk from the pier, but I was all island'd out!