Saint-Hilaire-de-Riez, France

How the Internet Reaches Saint-Hilaire-de-Riez

Saint-Hilaire-de-Riez is a coastal commune in western France, situated on the Atlantic seaboard of the Vendée department. Its position on the French Atlantic coast makes it a direct landing point for transatlantic submarine cable infrastructure, connecting the European continent to North America via the ocean floor. International internet traffic between France and the United States reaches — or departs from — this stretch of coastline through a single submarine cable that came into service in 2021.

Unlike major French hubs such as Marseille, which aggregate traffic from more than a dozen cables, Saint-Hilaire-de-Riez functions as a dedicated single-cable terminus. All transatlantic traffic routed through this landing point flows along one route: the Dunant cable, running westward across the Atlantic to Virginia Beach on the eastern seaboard of the United States.

The Cable Serving Saint-Hilaire-de-Riez

The Dunant cable is a 6,400 km transatlantic system that entered service in 2021. It connects Saint-Hilaire-de-Riez directly to Virginia Beach, Virginia, in the United States, forming a bilateral France–United States route across the North Atlantic. The cable's 6,400 km length is broadly consistent with the average cable length across France's wider submarine cable portfolio, which stands at 6,517 km. Dunant is a point-to-point system: its only two landing points are Saint-Hilaire-de-Riez and Virginia Beach, meaning there are no intermediate branch connections to other countries along its route.

Regional Context

France hosts 24 submarine cables across 19 landing points, making it one of the better-connected countries in Europe for submarine cable infrastructure. Saint-Hilaire-de-Riez is among the smaller terminuses in this national network, serving a single cable compared to Marseille's 13 or even nearby Cayeux-sur-Mer and Lannion, which each host 2 cables. Other single-cable French landing points include Ajaccio and Bastia in Corsica, both of which similarly serve more localised or specific connectivity needs rather than broad international aggregation roles.

What This Means for Connectivity

Because Saint-Hilaire-de-Riez is served by only one submarine cable, all international traffic routed through this landing point travels exclusively via Dunant to and from the United States. An outage on the Dunant cable would sever this particular transatlantic path entirely, with no alternative submarine route at this landing point. The destinations reachable directly through this cable are limited to the United States, specifically to the Virginia Beach landing on the American side.

For those seeking to understand how the French Atlantic coast fits into global internet topology, Saint-Hilaire-de-Riez illustrates a pattern common in national cable networks: a small number of highly specialised single-cable terminuses operating alongside large aggregation hubs. Rather than handling diverse international traffic, this landing point serves a precise transatlantic corridor, complementing the broader French network that fans out from hubs like Marseille toward the Mediterranean, Indian Ocean, and beyond.