It happened about 9:30 am (local time) on the island of Kauai, the county fire department said. The pilot, two skydive instructors and two tandem jumpers were believed to be on the plane.
Four of them were pronounced dead at the crash site, just outside Port Allen Airport. One man was taken to Wilcox Memorial Hospital, where he was pronounced dead.
The group was believed to have been part of a tour operated by SkyDive Kauai, county firefighters said. The company offers tours from Port Allen.
Company President David Timko said he didn't have any comment because the crash is under investigation. But he said he offers his condolences to the families of those killed. Kauai firefighters said the identities of the dead haven't been released.
More From This Section
The National Transportation Safety Board will work with officials to determine the cause of the crash. The Federal Aviation Administration will also investigate.
The plane was a single-engine Cessna 182H, FAA spokesman Ian Gregor said. It's unclear what led to the crash.
County lifeguards brought two people to shore from a single engine aircraft that was about 30 yards off the coast, Honolulu Fire Department Capt David Jenkins said.
The other person in the airplane wasn't injured, Honolulu Emergency Services Department spokeswoman Shayne Enright said.
State Department of Health data shows 20 visitors died in aircraft crashes in Hawaii from 2005 to 2014, including one skydiver.
The others were killed in plane, helicopter and light sport aircraft crashes. Over the same period, 24 residents were killed in air crashes, including four skydivers.