EXA Atlantic (formerly GTT Atlantic, Hibernia Atlantic) is a 12,200 km private transatlantic submarine cable system in the North Atlantic Ocean, connecting Canada, the United States, Ireland and the United Kingdom. The EXA Altlantic consists of EXA South and EXA North cables.

Hibernia Atlantic Submarine Cable System was ready for service on April 8, 2001, with a design capacity of 10.16 Tbps.

The Hibernia Atlantic Submarine Cable System was originally developed and owned by Hibernia Atlantic U.S. LLC (also konwn as Hibernia Networks), which held both domestic and international Section 214 authority (FCC 214 License) and a submarine cable landing license in the US. In 2017, GTT acquired all of the issued and outstanding shares, and therefore the control, of Hibernia NGS Limited and each of its subsidiaries. Hibernia Atlantic U.S. LLC is one of the subsidiaries soly owned by Hibernia NGS Limited.

In January 2017, GTT completed the acquisition of Hibernia Networks for $USD607 million (initial price was $590 million) , which includes Hibernia Express, Hibernia Atlantic and other assets.

In September 2021, I Squared Capital, an infrastructure private equity firm, acquired GTT's Communications’ infrastructure division for an initial $1.74bn in cash, and renamed the newly independent operating company EXA Infrastructure. The GTT Atlantic and GTT Express, as part of assets covered by the acquisition, are now renamed as EXA Atlantic (EXA South and EXA North) and EXA Express.