Rabaul Harbor sits within a massive volcanic caldera on the northeastern tip of New Britain island in Papua New Guinea, making it one of the most dramatically situated natural harbors in the Pacific. The harbor stretches approximately eight miles long and six miles wide — dimensions Gates himself notes on camera while scanning its waters. Beneath its surface lies a remarkable and largely uncatalogued graveyard of World War II wreckage, the legacy of Rabaul's role as a major Japanese military stronghold during the Pacific War. Local divers had long reported seeing submerged aircraft and vessels, fueling speculation that wreckage matching Amelia Earhart's Lockheed Electra could be among them. Gates brought side-scan sonar equipment to the harbor in the very first episode of Expedition Unknown, framing Rabaul as a potential final resting place for one of aviation history's greatest unsolved mysteries.
Rabaul established as a major colonial and later military port; its caldera harbor recognized as a strategic deep-water anchorage
Amelia Earhart disappears over the Pacific during her attempted round-the-world flight; some researchers later theorize her Electra could have come down near Papua New Guinea
Rabaul serves as a key Japanese military base during World War II; the harbor and surrounding waters become the site of intense Allied air and naval attacks, leaving hundreds of wrecks on the seafloor
Gates and dive expert Rod Pierce conduct side-scan sonar surveys of Rabaul Harbor in Season 1, Episode 1 of Expedition Unknown
Rod Pierce, the dive expert accompanying Gates in Rabaul Harbor, provided the key on-camera aircraft identification during the dives. When examining the second wreck, Pierce assessed the cockpit configuration and concluded it was consistent with a Grumman TBF Avenger torpedo bomber rather than Earhart's Electra — a determination Gates deferred to entirely, noting the Electra's short, narrow windows contrasted with the more open design they were seeing underwater.
Rabaul's wartime history helps explain why the harbor floor is so rich in wreckage. The town served as a major Japanese military base during World War II, and the surrounding waters were the target of sustained Allied bombing and naval operations. Hundreds of ships and aircraft are believed to rest beneath the harbor and nearby Simpson Harbor, making it a well-regarded site among wreck-diving communities — though the full inventory of sunken vessels and aircraft remains, by most accounts, incomplete.
The Earhart connection to Rabaul specifically rests on the testimony of local divers who believed they had seen wreckage consistent with a twin-engine aircraft. The broader theory that Earhart came down somewhere in the Pacific — potentially as a castaway, a prisoner of Japan, or simply a victim of fuel exhaustion over open ocean — remains one of aviation's most contested cold cases. Mainstream researchers and aviation historians have proposed numerous candidate sites across the Pacific, and no physical evidence definitively linked to Earhart's Electra has been confirmed at any location.
What the Expedition Unknown episode contributed was a methodical, sonar-assisted survey of one proposed area — honest in its ambition and honest in its outcome. Gates found genuine and historically significant WWII wreckage, including what appeared to be a Japanese Zero and an Allied Avenger with possible crew remains, but the Electra was not among them. The episode is a useful illustration of how Earhart investigations tend to go: serious effort, real discoveries, and the central mystery still stubbornly unresolved.
Rabaul Harbor occupies the interior of a volcanic caldera, meaning the dramatic hillsides surrounding the anchorage are actually the remnants of an ancient volcanic rim.
According to Gates' on-camera narration, the harbor stretches approximately eight miles long and six miles wide — a vast underwater search area even with modern side-scan sonar equipment.
The Grumman TBF Avenger found during the Expedition Unknown dive was a three-seat aircraft, and Gates noted on camera that what appeared to be the crew's remains were still inside the wreck.
The Mitsubishi A6M Zero examined during the dive was, according to Gates, a long-range fighter used from 1940 to 1945 and among the aircraft types involved in the attack on Pearl Harbor.
Rabaul and its harbor are generally accessible to visitors, and the region has historically attracted wreck divers interested in its WWII-era submerged aircraft and ships. Dive operators in the area may offer guided wreck dives, though travelers should check current local advisories and operator availability before planning a trip, as conditions and services can change. The volcanic landscape around the caldera is itself a significant draw, with active volcanic features visible from the harbor's edge.
Rabaul town is the immediate settlement adjacent to the harbor; the regional hub of Kokopo lies approximately 20 kilometers to the southeast and serves as the main administrative center for East New Britain Province.
Papua New Guinea's dry season, roughly May through October, is generally considered the more favorable period for diving and outdoor exploration in the region. Visibility in the harbor can vary depending on volcanic sediment and weather, so checking with local dive operators closer to your visit is advisable.
Normandy Beaches, France
Normandy Beaches share Rabaul Harbor's identity as a major WWII battleground with submerged wreckage, and Gates has investigated underwater and coastal WWII sites in both locations.
Lake Michigan
Lake Michigan has been the subject of underwater search and sonar-based investigations on Expedition Unknown, paralleling the methodology Gates used scanning Rabaul Harbor.
Indian Ocean
The Indian Ocean is one of the other broad geographic zones proposed by Earhart researchers as a possible crash site, connecting it thematically to the Rabaul Harbor investigation into her disappearance.