RNZ reports Laurent and Meherio Para, aged 34 and 29 respectively, were discovered by fishermen yesterday.
They had left the island of Huahine in the Society Islands heading for Maiao further south on their motorised fishing boat.
French Polynesia's air and maritime rescue service spent 55 hours looking for the pair over 70-thousand square kilometres of ocean and had stopped searching on Monday.
Meherio Para said they survived on a large fish they had caught and collected rainwater and used a tarpaulin for a sail.
She said her brother's experience as a fisherman saved them.