The couple, who have been dating for six years, wed in a civil ceremony on Saturday before celebrating with 500 of their closest friends and family.
The only official portraits of the wedding were posted by the Maison Valentino Instagram account with the Italian journalist, whose family boasts two cardinals at the Vatican, opted for an Haute Couture gown by the iconic designer.
They exchanged vows in front of just 70 people at the Salon des Glaces in Monaco's Pink Palace, with Prince Albert and his wife, Princess Charlene; Pierre's mother Princess Caroline and Princess Stephanie were among the regal attendees.
But it was all about the dress for Beatrice, whose style has landed her on Best Dressed Lists around the world.
"The House of Valentino is pleased to announce that Beatrice Borromeo wore a Valentino Haute Couture dress designed by Creative Directors, Maria Grazia Chiuri and Pierpaolo Piccioli, for her civil wedding with Pierre Casiraghi on July 25th at the Prince's Palace of Monaco. The wedding gown was created in a pale pink and gold lace silk chiffon," Valentino's Instagram post read.
Pierre is the seventh in line for the throne as grandson of Grace Kelly and Prince Rainier.
Beatrice studied at Columbia University's Graduate School of Journalism in New York City and met her royal other half while they were attending Milan's Bocconi University together.
They will mark their nuptials with a religious ceremony in Italy next week on Borromeo Island.