Hi matt...Seal diving at the isle of shoals is tricky,and can be dangerous if you don't know the exact rout to follow. Duck island is where you want to go.This is the most northern island of the 9 islands,and there is one approach route. There is a point on the northwest side of appledore island. Keep your back to this point and look at the east side of Duck island.Head straight SLOWLEY till you come to mingo rock on your right. Pick your way carefully between shag rock and mingo (just as gradydiver said). You will then be at the entrance to the amphitheatre. This is about 15 ft. deep, and it drops off to about 100 ft. on the east. this is a spectacular area for flora and fauna.The south side of Duck has loads of harbor seal,which will swim with you because they are courious. (federal regs. prohibit approach,but say nothing about the seals coming to you.On the north side of duck is a colony of gray seals,who are shy, but will come to you if you offer a mackral treat. These seals can run up to 700 lbs.and will make your summer.(bring a camera).I do shark research in the area so look for my cris-craft (porbeagle) and I'll be happy to answer any questions that you may have.( Oh! There is little to no surge in the amphitheatre because it is protected by rocks on the east,but outside the amphitheatre can be rough.Good luck,Dive safe,and PM me if you want more specific info.Look for me this summer,as I will be West of duck most days or to the east of Duck in deep water.I always have cold beer. PORBEAGLE