According to Genesis, Noah’s Ark floated for 150 days before the floodwaters receded.
Genesis says that the waters prevailed over the Earth for 150 days. This period is distinct from the 40 days and 40 nights during which rain fell. After the 150 days, the waters began to decrease, and the Ark came to rest on the mountains of Ararat.
The numbers are sometimes confused because the biblical flood narrative mentions several separate time periods, including seven days before the rain began, 40 days of rain, 150 days of prevailing waters, and the much longer total period before Noah left the Ark. The exact chronology depends on how the passages are harmonized, but 150 days is the explicit duration given for the waters prevailing.
The account then describes Noah sending birds to test whether dry land had appeared. These episodes mark the transition from the flood’s destructive phase to the gradual return of habitable land.