St. Thomas-St. Croix System

Overview

The St. Thomas-St. Croix System is a submarine cable that provides intra-territorial connectivity within the United States Virgin Islands. Spanning 183 kilometers, it links the islands of St. Thomas and St. Croix, as well as several other key locations within the territory. Operational since 1997, the cable plays a vital role in supporting local communications infrastructure, ensuring robust connectivity for residents and businesses in this Caribbean region. Its entirely domestic route within U.S. Virgin Islands waters makes it a critical asset for inter-island data transmission and network reliability.

Unlike international submarine cables that connect distant continents, the St. Thomas-St. Croix System focuses exclusively on local connectivity. This design ensures that the U.S. Virgin Islands maintain independent and direct communication links between their islands without relying on external systems. The cable's relatively short length reflects its regional focus, making it a unique component of the territory's telecommunications landscape.

Route and Landings

The St. Thomas-St. Croix System connects seven landing points, all located within the United States Virgin Islands. These landings include Banana Bay, Brewer's Bay, Flamingo Bay, Great Bay, and Vila Olga, which are situated on St. Thomas and nearby areas, as well as Christiansted and Frederiksted on St. Croix. The distribution of these landing points ensures comprehensive coverage across the territory's main islands.

Geographically, the cable crosses the Caribbean Sea between St. Thomas and St. Croix, two of the largest islands in the U.S. Virgin Islands. St. Croix, located farther to the south, hosts two landing points: Christiansted on the island's northeastern coast and Frederiksted on its western shore. On St. Thomas, the cable connects to multiple coastal locations, including Brewer's Bay near the island's airport and Vila Olga, which is closer to the capital, Charlotte Amalie. These strategic landings provide redundancy and enhance the resilience of the local network.

Ownership and History

The St. Thomas-St. Croix System is owned and operated by Virgin Islands Next Generation Networks, Inc., a local telecommunications provider focused on enhancing connectivity within the U.S. Virgin Islands. The cable was commissioned in 1997, making it the oldest operational submarine cable in the territory. Its deployment marked a significant milestone in the region's telecommunications history, as it was the first system to provide dedicated inter-island connectivity within the U.S. Virgin Islands.

Since its launch, the cable has supported the territory's growing demand for reliable telecommunications infrastructure. Over nearly three decades of service, it has remained a cornerstone of local connectivity, complementing newer international systems that have since landed in the region. Its enduring relevance underscores its importance to the U.S. Virgin Islands' communications network.

What Our Measurements Show

Our live monitoring of the St. Thomas-St. Croix System reveals performance metrics that highlight its operational efficiency. The cable's best round-trip time (RTT) is measured at 130 milliseconds, with an average RTT of 190 milliseconds across 48 monitored corridors. These figures indicate stable and consistent performance, suitable for the local connectivity needs it serves.

The relatively short length of the cable, combined with its intra-territorial focus, contributes to its reliable latency metrics. By connecting key locations within the U.S. Virgin Islands, the system ensures low-latency communication between St. Thomas, St. Croix, and other landing points. This performance is critical for supporting local businesses, government operations, and residents who rely on seamless inter-island communication. The cable's role in maintaining these connections underscores its importance as a regional infrastructure asset.