On several Indian coasts the ferry is public transport, not a boat trip

Where water divides a city, the boat is the short way

A road that goes around a bay can be many times longer than the line across it. Wherever that geometry occurs on the Indian coast — Kochi’s backwater channels, Mumbai’s harbour, the estuaries of Goa, the mouths of the Bengal and Assam rivers — a boat service exists because it is straightforwardly the quickest way for local people to get to work.

These are not excursions. They are timetabled services carrying people who have taken them a thousand times, usually cheap, usually crowded at the ends of the working day, and generally indifferent to whether a visitor understands the system.

That is exactly what makes them worth using. You cross the same water as a chartered boat, on a schedule, alongside the people whose city it is, and you arrive somewhere rather than being brought back to where you started.

Kochi is the clearest example in the country

Kochi is built across islands, peninsulas and a lagoon, and its ferry network stitches the parts together — the mainland at Ernakulam, the old port district at Fort Kochi, Vypin across the channel, Willingdon Island in the middle of it. For a great many residents the boat is the daily commute.

For a visitor the practical consequence is that Fort Kochi does not have to be reached by a long road loop through traffic. The crossing takes minutes, and it puts you in the middle of a working harbour with ships, fishing craft and the channel traffic moving around you.

Further south, the backwater ferries of Alappuzha and the Vembanad system perform the same function through the canals and lakes, connecting villages that have water frontage and no useful road. They are slower, they stop constantly, and they show you a landscape that the tourist houseboats mostly skirt.

Vehicle ferries exist where bridges do not

Some crossings carry vehicles as well as people, on flat-decked craft that load from a ramp. Goa retains several of these across its rivers, and they remain part of the actual road network rather than a heritage attraction — a queue of scooters and cars edges on, the ferry crosses, and everyone drives off the other side.

The pattern repeats in Assam and Bengal, where the rivers are wide and bridges are far apart, and where a vehicle ferry can save a detour of many hours. On the Brahmaputra it is the ordinary way to reach the large river islands.

These services are weather-dependent in a way road transport is not. High water, strong current, fog and storms all stop them, sometimes for days, and the alternative is the long way round. Anyone building an itinerary that depends on a river crossing should know what the detour costs before they need it.

They run on local logic and you have to read it

Ferry systems rarely explain themselves in English or in writing. Timings may be posted in the local language or not posted at all, the frequency changes between peak and slack hours, and the last service of the day is often much earlier than a visitor expects.

The reliable technique is to ask at the jetty, and to ask specifically about the return. Getting across is easy; being stranded on the far side because the last boat left at dusk is the standard mistake. Where a road alternative exists it is worth knowing what it is and roughly how long it takes.

Tickets are usually bought at a counter or from a conductor on board, and the crush at boarding time in a commuter port is genuine. Timetables, routes and operating hours are set locally and change, particularly with the seasons, so the current position needs checking on the spot rather than from an old account.

The monsoon rewrites the whole picture

Open-water services are the first thing suspended when the sea is rough. Harbour crossings in an enclosed bay usually continue; anything that crosses exposed water may not, and services to islands are subject to the same weather rules as any other small vessel.

Backwater and river ferries mostly keep running through the rains, since the water is sheltered, but river craft face their own seasonal problem in the opposite direction — in the dry months, falling levels can leave channels too shallow for a loaded boat, and routes get shortened or cancelled for depth rather than for storms.

None of this makes them unreliable in any sense that matters locally. It makes them a transport mode that answers to conditions, which is worth remembering if a connection matters. Give a ferry leg more slack in the timetable than you would give a bus, and treat a same-day onward flight after a crossing as an optimistic arrangement.