Telecommunications and connectivity: submarine cable dependence

Island connectivity is often described in terms of mobile coverage and broadband speeds. The determining factor is upstream of both: the submarine cables connecting the island to the internet at large.

The submarine cable layer

Everything international — web traffic, calls, banking, cloud services — travels through submarine fibre.

Characteristics for a small island:

• A small number of cables, sometimes very few
• Landing stations at specific coastal points
• Capacity purchased from cable operators, which is a major cost for local providers
• Regional cable systems connecting multiple islands in a chain

The risk that follows is concentration. Where an island is served by few cables, a single cable fault can degrade or interrupt international connectivity for the whole country — and repair requires a specialist cable ship, which may be days or weeks away.

This is why cable diversity, rather than domestic network quality, is the meaningful resilience question for island connectivity.

Why bandwidth costs more

• Capacity is bought wholesale from cable operators at prices set by volume
• Small volumes mean weaker purchasing terms
• Fixed network costs spread over few subscribers
• Limited competition in a small market
• Terrain raising the cost of domestic fibre deployment

Same structural pattern as electricity and freight. Small market size raises unit costs across every network industry, because all of them have high fixed costs and low marginal ones.

Domestic networks

• Mobile penetration is high, as across the Caribbean
• Mobile data is the primary means of access for many users
• Fixed broadband available in populated areas
• Coverage gaps in the mountainous interior
• The dependencies served with their own arrangements

The second point matters for anyone designing services for this market. Mobile-first is not a preference here but the actual access pattern, and services assuming a desktop fixed connection exclude a substantial share of users.

Resilience

• Storm damage to overhead distribution, as with electricity
• Power dependence — networks fail when power fails, unless backed up
• Cable faults requiring specialist repair vessels
• Satellite backup for emergency communications
• Regional coordination for restoration after events

The second is the one most often overlooked in continuity planning. A telecommunications network with intact infrastructure still fails if its sites lose power and battery reserves are exhausted, which is what happens in an extended post-storm outage.

This is why emergency communications planning for small islands treats power and telecommunications as one system rather than two.

Reading connectivity data

1. Distinguish subscriptions from users — multiple SIMs inflate penetration figures
2. Check whether advertised or measured speeds are reported
3. Note coverage by population versus by area, which differ greatly in mountainous terrain
4. Consider affordability, not only availability
5. Check the reference year, since this sector changes quickly

Point one produces the most inflated statistics in this field. Mobile subscription rates above 100 percent of population are common and reflect multiple SIM ownership rather than universal access.

Frequently asked questions