Schatz was appointed to the Senate seat by Hawaii Gov. Neil Abercrombie (D), who was ousted in his own primary Saturday night.
Hanabusa, the late Sen. Dan Inoyue's (D-HI) pick to succeed him, put up a notable challenge to Schatz, who had endorsements from prominent Democrats and more campaign cash.
Results from some of the precincts in Hawaii were delayed due to Tropical Storm Iselle. Two precincts delayed voting due to the storm.