Boaro, 29, joins the Middle East team from Tinkoff, which will disband at the end of the season, and Visconti, 33, leaves Spanish outfit Movistar.
“At Bahrain Merida Pro Cycling Team we are very pleased to welcome such talented cyclists as these two riders," said the team's general manager, Brent Copeland.
"We are sure they will contribute a very important part to the team and what we want to achieve, from our side we will go out of our way to make things as convenient as possible for them to be able to do their dedicated work in the best possible way."
The Bahrain Merida team is hoping to register with the Union Cycliste Internationale (UCI) as a top-level WorldTour team, taking up a position left vacant by the departure of the Tinkoff and IAM teams.
It is currently unclear which other riders the team has signed up for 2017, although it is rumoured that Alessandro Vanotti and Valerio Agnoli will join the team from Astana, Nibali's current team. Diego Ulissi and Louis Meintjes could also follow manager Copeland to the squad from Lampre-Merida.
The squad is backed by Bahrain's Prince Nasser bin Hamad Al Khalifa, and is evidently banking on being invited to one or more Grand Tours, whether as a WorldTour team or not.
In June, human rights groups Bahrain Institute for Rights and Democracy (BIRD) and European Center for Constitutional and Human Rights (ECCHR) sent a joint letter to the UCI urging them not to accept the Bahrain team's application for the WorldTour due to the controversial human rights record of Prince Nasser.
The team will be registered in Bahrain but have a base in Italy to access European races.
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