About 50 Darwinites and visitors, including a contingent of the United States Marine Rotational Force - Darwin, gathered to remember the hundreds of sailors, officers and airmen who died in the Battle of the Coral Sea in 1942.
The ceremony took place at sunset at Darwin's USS Peary memorial.
Also in attendance were Administrator of the Northern Territory (NT) David Connolly, representatives of the federal and NT governments, senior officers of the Australian Defence Force and members of local community groups.
Although the Coral Sea lies in waters east of Townsville, the scale of the battle 84 years ago left the future of Australia hanging in the balance.
The fighting lasted four days and marked a significant turning point during World War II.
It was the first naval engagement in history in which the opposing fleets never actually saw each other.
Instead, the battle introduced a new mode of warfare, relying on air power rather than naval gunfire.
The Japanese fleet was forced to withdraw and did not attempt another advance on Port Moresby.
There was no clear winner, but there was a devastating loss of life, with three shipwrecks marking the final resting place for Japanese and allied personnel of the Battle of the Coral Sea.
'There is a price for freedom, and we cannot become complacent or take it for granted.'
The Australian American Association of the NT hosted the annual memorial to recognise the sacrifices of all, and the stepping stone the Battle of the Coral Sea provided the allied forces as they pushed north through the Pacific.
Commanding Officer HMAS Coonawarra Captain Bernadette Alexander spoke at the service, detailing the pivotal shift in the war.
"The Battle of the Coral Sea had great consequences for war, but it also had great consequences for peace because it forged an enduring bond between Australia and the United States," Captain Alexander said.
"We know we are always stronger when we are fighting together."
Local Navy cadets Petty Officer Scott Dunk and Leading Seaman Samantha Mercader read statements from the President of the United States Donald Trump and Australia's Prime Minister Anthony Albanese.
President of the Australian American Association of the NT, Bradly Torgan, spoke of the tremendous cost of the battle, including the loss of 656 American lives.
"There is a price for freedom, and we cannot become complacent or take it for granted," Mr Torgan said.
"Eternal vigilance means never forgetting the cost of the loss of freedom. It fades when we stop watching and stop questioning."
While fierce adversaries during the Battle of the Coral Sea, Japan is now one of the Australia's and the United States' closest regional partners and allies.
The service highlighted the enduring alliance between Australia and the United States, which remains visible in NT, where United States Marines have rotated through the Top End dry season for the past 15 years.
