At Astana, he won the 2013 Giro d'Italia, the 2014 Tour de France and again the Giro this May.
He is the first rider officially named in the Middle East team due to debut next season with the backing of Prince Nasser bin Hamad Al Khalifa.
"I was immediately fascinated by the idea of a strong project plan built around me," Nibali explained. "I have believed in the team from day one, because it has a clear vision and is to be carried out by some of the best professionals in the sport.
"This trust and confidence in me made me take the final decision for this new exciting adventure of my career. I can't wait to meet their expectations at the most important races in the world wearing the jersey of Bahrain-Merida."
The 31-year-old from Sicily will bring along his trainer Paolo Slongo and masseur Michele Pallini. Long-time teammates Alessandro Vanotti and Valerio Agnoli should also be jumping the Astana ship for Bahrain.
South African Brent Copeland will switch from managing Lampre-Merida. He is also taking the Taiwanese bike sponsor Merida with him as the team's co-sponsor.
Diego Ulissi and Louis Meintjes are some of the current Lampre riders expected to make the switch.
An inside source told Cycling Weekly in May that Prince Nasser's team will begin with a modest budget of around £12.6 to £15.1 million (€15 to €18m). Team Sky's in comparison is around £24 million.
Nibali will make the switch from his present Specialized race bike
The team will base itself near Bergamo, Italy, next door to the FSA components headquarters in Busnago.
The team's Merida bikes will be fitted with the Italian equipment and the cyclists will wear Italian clothing from Sportful, in Bahrain's red and gold colours.
Another source told Cycling Weekly that the team will take over the Lampre-Merida WorldTour licence instead of asking for one of the ones that IAM Cycling and Tinkoff will leave free at the end of this 2016 season.
Lampre-Merida's general manager, Giuseppe Saronni will apply for a professional continental licence for 2017.
WorldTour teams have the right to race in all the races in the series, including the Tour de France. The UCI announced that it will expand the WorldTour series from 27 to 37 events, including RideLondon.
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