The Spain international has completed his move from Real Madrid to the San Paolo for a fee believed to be in the region of £10.3 million on a four-year deal
The Spain international has struggled to cement a firs-team place during his four years at the Santiago Bernabeu, making just 27 appearances last term.
The 27-year-old has been linked with a move to the Serie A outfit throughout the summer and has now sealed a reported €12 million (£10.3m) switch to the San Paolo, signing a four-year deal.
"Napoli have officially signed Raul Albiol," the club's offical website read. "The 27-year-old Spanish defender arrives from Real Madrid and has signed a contract for four years."
Rafa Benitez has also brought the former Valencia man's old Madrid team-mate Jose Callejon to the club this summer and have also signed Santos keeper Rafael amongst others.
The Neapolitans finished second in Serie A last term, but lost coach Walter Mazzarri to Inter and star forward Edinson Cavani to Paris Saint-Germain this summer.