Why Cape Town-Kourou Internet Traffic Detours via London and the US
When data is sent from Cape Town (South Africa) to Kourou (French Guiana), logic suggests that the route should be direct: across the Atlantic Ocean, minimizing latency. However, reality, as measured by GeoCables on October 1, 2026, paints a completely different picture. Instead of taking the direct 8,566 km path, packets are diverted by 7,053 km from the shortest line, passing through London, Newark and even Atlanta before finally reaching Kourou. The resulting latency (RTT) is 399 ms, nearly five times the theoretical minimum of 86 ms that would be possible with an ideal route.
Why does traffic pass through London and the US?
The main reason for this detour is the routing and peering arrangements between networks. On the traffic's journey, major global transit operators such as Zayo Bandwidth (AS6461) and SEACOM Limited (AS37100), as well as local providers including Xneelo (Pty) Ltd (AS37153) in South Africa and WAYSCOM (AS27806) in French Guiana, are involved. Traffic passes through London, Newark and other hubs because there are no direct connections between South Africa and French Guiana, and peering between local providers and global operators is often oriented toward major traffic exchange points such as London and Newark.
Transit economics also play a role: providers choose routes that minimize their data transfer costs, even if this increases latency for the end user. London, one of the largest global internet traffic exchange hubs, and the US remain key transit regions due to their high density of backbone cables and exchange points.
Practical implications for users
A latency of 399 ms is a significant issue for many applications. Video calls over such routes suffer from noticeable lag, causing discomfort during communication. In online gaming, where every millisecond matters, such latency makes competitive matches virtually impossible. Cloud services like Google Drive or Dropbox also lose efficiency: server response times increase, and file synchronization slows down.
This is especially critical for financial operations, such as stock trading. With a latency of 399 ms, traders lose the ability to quickly react to price changes, which can lead to significant financial losses.
Infrastructure context: why does this happen?
South Africa and French Guiana are regions with relatively limited direct submarine cable connections to each other. While Cape Town has landing points for cables like SEACOM and SAT-3/WASC, they are primarily oriented toward connecting to Europe and North America. French Guiana, on the other hand, is connected to the world through cables like Americas-II and Kanawa, which lead to the US and the Caribbean. The absence of a direct cable between these two regions forces traffic to pass through intermediate hubs in Europe and North America.
Additionally, peering policies and agreements between operators may also play a role. For example, if local providers lack direct agreements with major global operators, traffic is forced to pass through additional hubs.
Real-world events near the route
The infrastructure landscape also includes recent events recorded by GeoCables. For instance, in South Africa on June 5, 2026, there was a green alert due to flooding, but it occurred 593 km away from Cape Town and did not affect routing. In Europe, floods were reported in France, the Netherlands and Belgium during the summer of 2026, but these events are also unrelated to this detour. These occurrences highlight the complexity of the global network: even in the absence of direct impacts, external factors can add context to routing decisions. However, in this case, the reason lies solely in peering arrangements and infrastructure.
Thus, the detour between Cape Town and Kourou is a vivid example of how the global internet infrastructure can deviate from the ideal. GeoCables continues to monitor such cases, uncovering the hidden mechanisms of routing and their impact on users.
