She began her career working for the family business which she would go on to inherit after the death of her father Costantino, the eldest son of Bulgari founder Sotirio Bulgari. Alongside her sister and cousins, she ran the business for several years before deciding to part ways and branch out and start her own business.Prevented from using the Bulgari name professionally she first named her company Crisart before changing it to her own Christian name and the initial of her surname, Marina B. She opened her first showroom in Geneva and launched a range of bold and colourful collections such as Onda and Pneu focusing on fine quality gold work set with a rainbow of coloured gemstones highlighted with pavé diamonds.
During the 1980s she released a succession of collections, unified by their unapologetically Italian flavour and their chic, joyful spirit. She designed a signature cut and shape which falls part way between a pear shape and a triangle and which can be found throughout her jewellery. Her pieces found favour with many glamorous women of the time and were worn by stars such as Sophia Loren, Elizabeth Taylor and Princess Grace of Monaco, all of whom were renowned for their style. The firm enjoyed much success and opened independent stores in Milan, London, Paris, New York, Jeddah and Tokyo.
Marina moved to Monaco in 1993 to enjoy the mix of beauty and security and continued to design jewellery until her retirement. In 1999 she sold her company, including all stock and her extensive and meticulously kept archives, to the Saudi Arabian Sheik of Jeddah, Ahmed Fitaihi.