01 DragonFlight
02 DragonQuest
02B the first two chapters of The white Dragon
03 DragonSong, 
04 DragonSinger, 
05 DragonDrums, 06 The White Dragon, 
07 Moreta, 
08 Nerilka's Story, 
09 DragonsDawn 
10 Chronicles of Pern, 
11 The Renegades of Pern, 
12 All the Weyrs of Pern, 
13 The Dolphins of Pern, 
14 The Skies of Pern. 
XX Red Star Rising (DragonsEye in the USA) and Masterharper of Pern pretty much stand alone and could be read at any point after the first two trilogies. 