Interisland

Interisland is an adjective used to describe relations, services, or movement between islands within an archipelago. In geography, it denotes interactions among islands rather than within a single landmass. In transportation planning, interisland refers to routes, facilities, and services that connect two or more islands.

Interisland travel is typically supported by ferries, catamarans, and other vessels designed for coastal or open-water passages. In archipelagic regions where land links are limited or absent, interisland air service may supplement waterborne transport, with scheduled flights operating between major islands. Interisland cargo networks move goods such as food, fuel, and consumer goods between ports within an archipelago, often using multi-port shipping regulations and port infrastructures.

The term is commonly applied to regions with pronounced island geography, such as Hawaii, the Aegean, the Philippines, the Caribbean, and the Balearic Islands, though it can also describe shorter connections between adjacent islands within larger island chains. Enterprises and governments study interisland networks to improve reliability, reduce travel times, and support tourism and local economies.

Challenges to interisland systems include weather and sea conditions that disrupt schedules, seasonal demand variability, port capacity limits, and the need for safety and environmental protection measures. Successful interisland networks balance transportation efficiency, environmental sustainability, and resilience to natural hazards.

See also: archipelago, ferry, intercity, transport network.