If you are in south Italy: Autosole A1 to Firenze; Firenze Mare A11 and finally Livorno Genova A12. If you are in North Italy: Autosole A1 to Parma; Cisa A15 to Santo Stefano and finally Genova-Livorno A12. The highway A12 exit : Carrara
The Carrara Avenza (MS) station is well served from the most important Italian cities; once in Carrara "navettes" will take people directly to Marina di Carrara.
Genova, Pisa and Florence. By the airports you can reach Marina di Carrara by taxi, bus and train. They will take you directly in Marina di Carrara even if they will also stop in every important place.