Full of adrenaline and amid terrifyingly close explosions, Ted Bernays saw a US aircraft carrier sink into the Coral Sea.
He'd just turned 18 .
"Oh it was frightening, for sure," the 92-year-old told AAP ahead of the pivotal battle's 75th anniversary.
"We were striked by dive bombers and torpedo bombers but they didn't hit us.
The Battle of the Coral Sea was fought southwest of the Solomon Islands and east of New Guinea from May 4 to 8, 1942.
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It was the first decisive halt to the Japanese push south towards Australia during WWII, shattered the myth Japan was invincible and paved the way for the Allies' eventual victory.
It was also the first aircraft-carrier battle and stopped a planned Japanese sea invasion of Port Moresby.
Mr Bernays, who turned 18 two days after the battle started, said he had no idea he was part of a significant moment in history as he loaded an anti-aircraft gun on the HMAS Australia.
"The ordinary serviceman never knew what was really happening ... or where he was going to next," he said
"We were piped to stand by for this attack ... but that's about all."
Events have been organised around the country to mark the battle, which was one of the first times Australia and the US fought together.
Prime Minister Malcolm Turnbull's attendance at a remembrance event in Townsville on Monday was scheduled ahead of his departure for New York for his first face-to-face meeting with President Donald Trump at a commemorative dinner on Thursday.
The battle was the first time opposing ships did not fire at each other, with aircraft delivering all attacks.
The US lost three ships including an aircraft carrier and 66 aircraft in the battle.
Japan lost five vessels and 77 carrier aircraft.
More than 1600 men were killed or injured.
