"There are no survivors," said Promech Air, the plane's operator.
Because of poor weather conditions, the body recovery process won't take place until today, Friday 26th June, the Alaska State Troopers said.
The floatplane, crashed in steep, mountainous terrain about 25 miles northeast of Ketchikan. Authorities haven't determined why it went down.
The plane was on a shore excursion, sold through Holland America Line. A private helicopter pilot reported seeing the plane's wreckage against a granite rock face, 800 feet above Ella Lake.
"We are incredibly distressed by this situation, and our thoughts and prayers are with those on board the plane and their families," Holland America said.
The 8 passengers were from the MS Westerdam, which left Seattle on Saturday for a seven-day round-trip cruise.
The plane had taken off on a tour of the 2-million-acre Misty Fjords National Monument, accessible only by floatplanes or boats.
The names of the victims will be withheld until family members are notified.
"There is nothing I can say that can alleviate the pain and overwhelming sense of loss that we and the loved ones of those affected are feeling," said Marcus Sessoms, Promech Air's president. "At this moment, all of us share the pain and anguish of this terrible event."