Ferries and Speedboats from Phuket and Krabi to Ko Phi Phi are not running with the full timetable at the moment and it is a bit difficult to find the valid timetables. These links to the Ferry- and Speedboat-Companies will help you:
Krabi to Ko Phi Phi Island:
Kanichta Speedboat, every day.
URip ferry, every day.
Arisa Speedboat, every day.
Phuket to Ko Phi Phi Island:
Andaman Wavemaster Speedboat
PP Sabai Marine Speedboat
Phi Phi Cruiser Ferry
Phi Phi Logistic and Tour Speedboat
Railay East to Ko Phi Phi Island:
Koh Yao Sun Smile Speedboat