The Firmina subsea cable is an open cable connecting the East Coast of the United States to Las Toninas, Argentina, with additional landings in Praia Grande, Brazil, and Punta del Este, Uruguay.

The  Firmina cable is named after Maria Firmina dos Reis (1825 - 1917), a Brazilian abolitionist and author whose 1859 novel, Úrsula, depicted life for Afro-Brazilians under slavery. A mixed-race woman and intellectual, Firmina is considered Brazil’s first novelist. 

The Firmina subsea cable is the longest cable in the world capable of running entirely from a single power source at one end of the cable if its other power source(s) become temporarily unavailable—a resilience boost at a time when reliable connectivity is more important than ever. 

The Firmina subsea cable consists of 12 fiber pairs, being built by Google.

SubCom is the supplier of Firmina cable project.

The Firmina cable system is expected to be ready for service by the end of 2023.