The turtles, along with two eight-year-old hawksbill turtles, were rehabilitated for six months at the Australian Seabird Rescue sea turtle hospital at Ballina before their release.
Rochelle Ferris from Australian Seabird Rescue said the three juveniles were the remaining survivors of 10 green turtles that were washed up after big seas and storms at the end of May.
Each had swallowed plastic, which made them ill and underweight.
Green and hawksbill turtles are both protected species.
A crowd gathered to watch the turtles make their way to the sea.
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