Why Subsea Cables Are Rushing Toward a Quantum Future

Quantum-ready encryption moves from concept to trials as operators test future security models

14 Nov 2025

The global subsea cable sector is entering a period of reassessment as operators examine how quantum-resilient encryption could shape future security frameworks for the networks that carry most international data traffic. Researchers and analysts say the shift reflects rising concern about long-term risks to systems that transmit more than 95 per cent of global communications.

Early proposals outline new encryption architectures for ocean-spanning fibre systems, including methods that distribute key material across internal paths to make intrusion harder. But these ideas remain largely theoretical. No large-scale quantum-secure cable system has yet been deployed, and most work is still confined to laboratories, controlled field trials and limited quantum-safe services offered over existing terrestrial and subsea routes.

TI Sparkle is among the few operators to move from proofs of concept to early commercial services on parts of its backbone. Analysts say this reflects growing interest in long-term protection for strategic routes, even though other major providers have not made comparable public commitments. Pressure from cloud platforms, governments and financial institutions is helping sustain the discussion as operators consider how quantum-era risks could influence future network design.

Heightened geopolitical tension is adding urgency. Subsea cables have become strategic assets in global competition, prompting regulators in the US and Europe to tighten expectations for both physical resilience and digital safeguards. Recent assessments from government and industry groups warn that threats to submarine infrastructure are evolving faster than traditional defences, encouraging early examination of quantum-ready approaches.

Progress remains slow. High development costs, limited real-world testing and uncertainty around emerging standards continue to restrain adoption. Yet many experts argue that early investment could help operators secure future partnerships with hyperscalers and defence-aligned organisations once the technology matures.

As quantum-secure concepts advance from research studies to field trials and commercial planning, the subsea cable industry faces a potential reshaping of long-term strategy. The transition is at an early stage, but momentum behind new security models is building.