Charlie Chan in Honolulu

Renowned detective Charlie Chan leads the shipboard investigation, balancing his calm logic with a fatherly concern as he races to return to the hospital for his newborn grandchild. He reads people quickly, pieces together clues from a motley crew of criminals, heiresses, and crew members, and unmasks the killer through careful deduction. His measured demeanor masks a sharp, relentless drive to bring truth to light.

The blunt, ambitious 'number two' son who boards the ship pretending to be Charlie Chan to prove his investigative chops. His bold plan creates tension and danger, and he participates in the staged 'controlled fire' attempt to flush out the killer. Despite his impulsiveness, he remains loyal to his father and helps steer the investigation toward the truth.

The younger Chan brother who accompanies Jimmy on the ruse. He provides a child’s perspective within the intensity of the investigation and helps move the plot forward through the brothers' schemes. He is part of the comic relief and nerve-wracking moments.

A secretary who becomes the only witness in the cabin where the murder takes place. She is drawn into the investigation as Chan pieces together the truth from her testimony and the uncertainties among the passengers. Her presence on the ship adds an element of vulnerability and resourcefulness.

An heiress entangled in a tug-of-war divorce settlement, her fortune and motives draw suspicion as the murder unfolds. Once a possible suspect, she becomes a central figure whose relationships with others illuminate the web of greed and betrayal on board. Her fate ties directly into the missing cash and the case's resolution.

Captain of the freighter Susan B. Jennings, focused on delivering cargo while the murder investigation unfolds. He navigates the crew’s tensions and the ship’s schedule, maintaining order as the danger on board escalates. His leadership frames the backdrop of the voyage as a pressure cooker for crime to emerge.

A deckhand known for walking his pet lion Oscar on the main deck, a troubling sight that adds to the ship's odd atmosphere. He becomes entwined in the gun’s transfer, ultimately returning it to Chan and helping move the investigation forward. His actions are tied to the mystery’s turning points.

An eccentric scholar who boasts of keeping a human brain alive in formaldehyde, a detail that highlights his unsettling curiosity and the film’s atmosphere of odd science. He becomes a suspect with a flair for dramatic revelations and unusual methods. His interactions with Judy Hayes and others add tension to the shipboard mystery.

A criminal accused of extradition to the USA, part of a crew of criminals marked for murder and deception on the voyage. He is part of the danger and is used by Chan to sift truth from disguise. He serves as a foil to Chan’s disciplined investigation.

A detective who travels with Johnny McCoy, his presence on board complicates the case and intersects with Chan's inquiries. He is a figure of law and order whose interactions reveal the web of schemes aboard the ship. His role showcases law enforcement’s dogged pursuit of truth.

A nurse who appears in the hospital sequence, tending to Chan’s daughter as she prepares to give birth. Her presence underscores the human stakes in the crisis aboard the ship and at the hospital. She provides professional calm amid the tension and drama.