Is it a rowboat, or a canoe? I could do a canoe with one paddle for a long distance, but a rowboat would be hard to keep up if the island was more than a few miles from wherever I wanted to try to go.
It also depends on what's available on the island... if it's got trees and edible plants and animals, I'd take the matches to make my life easier while I tried to construct my canoe. If the island was just barren rock, I'd take my chances with the rowboat.
I would only choose the cell phone if I had some kind of solar cell or other battery charger.