The ship capsized 20 months ago and Italy's national Civil Protection agency waited until sea and weather conditions were forecast for dawn today before giving the go-ahead. The Civil Protection agency said the sea and wind conditions "fall within the range of operating feasibility".
The Concordia struck a reef near Giglio Island's coast in January 2012, took on water through a 230-foot gash in its hull and capsized just outside the harbour. Thirty-two of the 4200 passengers and crew members died.
Engineers have never before tried to right such a huge ship so close to land. If the operation succeeds, the Concordia will be towed away and broken up for scrap.
Salvage experts had originally hoped to right the 115,000-ton vessel last spring, but heavy storms hampered work. Crews have raced to get the Concordia upright before another winter season batters the ship.
The operation involves dozens of crank-like pulleys slowly rotating the ship upright before tanks are filled with air to help float the ship up off the reef.