No, both are about 660 km from Hua Hin, journey time by bus about 10 hrs+. I see no point heading to Phuket for a short trip.
Krabi is great for scenery.
Bbut if you want scenery you can find that south of Hua Hin around Prachuap Khiri Khan Town, for snorkeling island style Koh Talu island is about 2.5 hrs by road and boat south of Hua Hin.
For busier islands + snorkeling Koh Tao is bus + ferry from Hua Hin, about 6 hours. There is also the coastline south and inland scenic areas around Hua Hin and the coastal area, not Krabi, but as said that is about 660 km each way
Edited: 1:15 am, September 21, 2012