EXA Express: transatlantic submarine cable connecting the UK, Ireland, and Canada
The EXA Express is a submarine telecommunications cable spanning approximately 4,600 kilometers, linking
Brean in the United Kingdom,
Cork in Ireland, and
Halifax in Canada. Owned and operated by EXA Infrastructure, the cable is listed as in service and has been operational since 2015, according to GeoCables records. Its transatlantic route plays a key role in connecting Europe and North America, providing high-speed data transmission across the Atlantic Ocean.
What makes the EXA Express particularly interesting is the lack of publicly disclosed technical specifications, such as its design capacity, fiber pair count, supplier, and specific technologies employed. This absence of information leaves room for speculation, but without operator documentation, these details cannot be confirmed. Additionally, live latency measurements from remote probes show a significant difference between theoretical and real-world performance, underscoring the complexities of measuring submarine cable latency.
Quick facts
| Name | EXA Express |
| Length | 4,600 km |
| Ready for Service (RFS) | 2015 (GeoCables database) |
| Owners | EXA Infrastructure |
| Status | In service |
| Design Capacity | Not disclosed |
| Fiber Pairs | Not disclosed |
| Supplier | Not disclosed |
| Technology | Not disclosed |
| Landing Points | Brean (United Kingdom), Cork (Ireland), Halifax (Canada) |
| Other cables at Halifax | EXA North and South |
Route
The EXA Express connects three key landing points: Brean in the United Kingdom, Cork in Ireland, and Halifax in Canada. Brean is located in southwest England, near Bristol, and serves as a major hub for submarine cables landing in the UK. Cork, on the southern coast of Ireland, is a strategic landing site for cables linking Europe to North America. Halifax, situated in Nova Scotia, Canada, is a prominent landing point for multiple transatlantic cables, including EXA North and South, which are also operated by EXA Infrastructure.
The geographic corridor of the EXA Express provides a direct transatlantic route, bypassing traditional landing points in mainland Europe, such as France or Spain. This routing may offer advantages in terms of latency and resilience for certain data flows.
Why it was built and what it carries
The EXA Express was built to address growing demand for high-capacity, low-latency connectivity between Europe and North America. With the proliferation of cloud computing, streaming services, and international data exchange, transatlantic cables like EXA Express serve as essential infrastructure for global internet traffic. While exact details of its design capacity and traffic types are not publicly disclosed, it is reasonable to assume that the cable supports a mix of enterprise, carrier, and content provider traffic.
In addition, the cable's landing points suggest a focus on connecting data centers and telecommunications hubs in the UK, Ireland, and Canada, further facilitating international connectivity.
History: what can be established
GeoCables records indicate that the EXA Express was ready for service in 2015. However, industry sources occasionally report conflicting dates for submarine cable commissioning, often due to delays in construction, testing, or regulatory approval. In this case, no alternative RFS year has been identified, so the 2015 date appears reliable.
EXA Infrastructure, the cable's owner, operates a portfolio of submarine and terrestrial cables across Europe and North America. The EXA Express is part of its strategy to provide high-performance connectivity between these regions.
Capacity and technology
Publicly available data does not disclose the design capacity, fiber pair count, supplier, or specific technologies used in the EXA Express cable. Without operator documentation, attributing these details would be speculative. Modern submarine cables typically employ dense wavelength division multiplexing (DWDM) technology to maximize capacity, but whether this applies to EXA Express cannot be confirmed.
Latency: the physics
Theoretical latency calculations for the EXA Express, based on its 4,600 km length, yield a one-way light propagation delay of approximately 22.5 milliseconds and a round-trip time (RTT) floor of 45.1 milliseconds. These calculations assume light traveling through fiber at speeds between 200,000 and 204,000 km/s.
Live latency measurements, however, show significantly higher RTTs. Remote probes recorded a minimum RTT of 80.9 milliseconds from Brean to Halifax and 82.5 milliseconds in the reverse direction, with average RTTs of 87.0 milliseconds in both cases. These discrepancies arise from additional delays introduced by land tails, terminal equipment, routing, and internet congestion. It is important to note that these measurements reflect the full internet path, not just the cable itself.
Redundancy: what happens if it breaks
If the EXA Express experiences a fault, redundancy is provided by other submarine cables in the corridor. Halifax serves as a landing point for EXA North and South, which could reroute traffic in the event of a disruption. Additionally, other transatlantic cables landing in the UK and Ireland, such as those operated by other providers, may offer alternative paths.
Repairing submarine cables typically involves deploying specialized cable-laying ships equipped with tools to locate, retrieve, and repair the damaged segment. Repairs can take weeks, depending on the severity of the fault, weather conditions, and the availability of repair vessels.
Bottom line
- The EXA Express spans 4,600 km, connecting Brean (UK), Cork (Ireland), and Halifax (Canada).
- Owned by EXA Infrastructure, it has been in service since 2015 (GeoCables records).
- Design capacity, fiber pair count, supplier, and technology are not publicly disclosed.
- Theoretical RTT floor is 45.1 ms, but live measurements show RTTs averaging 87.0 ms.
- Redundancy is supported by other cables in Halifax and the transatlantic corridor.