Hazards and resilience of subsea telecommunications connections for small islands

Small islands are among the most telecommunications-dependent communities on Earth, yet often the least resilient to network disruption, despite their importance for communications, education, healthcare and economic activity. However, global assessments of subsea cable vulnerability have largely overlooked the specific hazards and structural constraints affecting small islands. Here, we assess telecommunications resilience for small islands by integrating a 40-year global database of 5113 subsea cable faults with spatial analyses of environmental and anthropogenic hazard exposure. We analyse 24 island and island groups worldwide, representing diverse geological, economic, and oceanographic settings, and evaluate hazard exposure related to their offshore environments.
We find that island-proximal environments are disproportionately hazardous for subsea cables, with over 75% of faults on island-connecting systems occurring within 300 km of island coastlines. Globally, 71.4% of faults are attributed to anthropogenic causes, and logistic regression shows that increased anthropogenic exposure significantly raises the likelihood of fault occurrence (odds ratio = 2.22, p = 0.006). In contrast, no significant relationship is observed between natural hazard exposure and fault occurrence (p > 0.4), suggesting that route design and engineering mitigation effectively reduce impacts from routine natural processes. However, extreme natural events can still cause widespread, multi-cable system failures.
Small Island Developing States (SIDS) are particularly vulnerable, with fewer international cable connections (mean 3.9 vs 6.9 for non-SIDS) and greater distances from repair hubs (∼2200 km vs ∼1800 km), increasing both the likelihood and duration of outages.
These findings demonstrate that cable vulnerability is spatially concentrated and hazard-type dependent, requiring region-specific resilience strategies. Strengthening telecommunications resilience for small islands will require not only improved engineering and hazard assessment, but also increased network redundancy, regional cooperation, and targeted investment.