Water transport plays a bigger role in Brazil and Argentina than many visitors expect — not just for reaching offshore islands, but as a genuinely practical way to cross between the two countries, and even to get around within their biggest cities. From the short hop across Rio's Guanabara Bay to the international crossing of the River Plate estuary, here is how ferry travel works in this part of South America.
Crossing the River Plate: Buenos Aires to Uruguay
The most-used international ferry route in the region is not between Brazil and Argentina at all, but between Buenos Aires and Uruguay, across the wide, brown River Plate estuary. Buquebus is the dominant operator, running frequent daily crossings from Buenos Aires to Colonia del Sacramento (a UNESCO World Heritage colonial town, about 1 hour by fast ferry) and directly to Montevideo (around 2.5 hours). Colonia Express is a lower-cost competitor on the Colonia route, also running multiple times a day.
This crossing is popular both as a day trip from Buenos Aires — Colonia's cobbled streets are an easy half-day visit — and as a genuine international transport link, since it is often quicker and more pleasant than flying between the two capitals once airport time is factored in. Reserve ahead in the Southern Hemisphere summer (December–February), when demand from both tourists and Argentines crossing for weekends in Uruguay is highest.
Rio de Janeiro: the Niterói ferry
Within Brazil, the best-known passenger ferry is a genuine commuter service: the crossing of Guanabara Bay between central Rio de Janeiro and the city of Niterói on the opposite shore. Operated as part of Rio's public transport network, boats run frequently throughout the day, taking around 15–20 minutes and offering a striking view back across the bay to Sugarloaf Mountain and the Rio skyline — arguably one of the most scenic short ferry rides anywhere, for the price of an ordinary public transport fare. It is used daily by commuters but is equally worthwhile as a cheap, easy excursion for visitors.
Coastal and island boats around Rio
Beyond the Niterói crossing, boats play a supporting role in reaching several of the islands and coastal towns around Rio de Janeiro state. Ilha Grande, a largely car-free island of forest and beaches, is reached by ferry or speedboat from Angra dos Reis or the smaller port of Conceição de Jacareí — there is no bridge or direct road link, so a boat crossing is unavoidable. Services range from slower municipal ferries to faster, pricier speedboat operators aimed at tourists, with the speedboats cutting the crossing to well under an hour versus a couple of hours on the slower ferry.
These coastal boat connections work well combined with an overland trip down Brazil's Costa Verde — see our Rio to Paraty guide for the bus route along the same stretch of coast, which passes close to the jumping-off points for Ilha Grande.
Ferries elsewhere on the River Plate and Paraná
Away from the main Buenos Aires–Uruguay crossings, smaller passenger and vehicle ferries operate at various points along the River Plate and the Paraná Delta, including local services around Tigre, a popular delta town just outside Buenos Aires reached easily by train, from which small boats explore the maze of channels and riverside communities of the delta itself — a slow-travel day trip in its own right rather than a point-to-point transport link.
Practical booking notes
Buquebus and Colonia Express both allow online booking in advance, which is worth doing for the Buenos Aires–Uruguay crossings, especially around weekends, holidays and the Southern Hemisphere summer. Passports are required for the international crossing even though it can feel like a short hop — Uruguayan and Argentine border formalities are typically handled at the terminal before boarding, not on arrival, so allow extra time before departure. Rio's Niterói ferry, by contrast, is turn-up-and-go public transport with no booking needed, and fares are paid the same way as any other city bus or metro trip.
If you are combining the ferry crossing with onward travel into Uruguay or continuing around the region overland, book ferry and bus legs separately rather than expecting a single through-ticket — the companies operate independently, and connections are rarely tightly coordinated.
Frequently asked questions
What is the ferry from Buenos Aires to Uruguay called?
Buquebus is the main operator, running both fast (around 1 hour) and slower (around 3 hour) services to Colonia del Sacramento, and a longer direct crossing to Montevideo. Colonia Express is a cheaper alternative on the Colonia route.
Do I need a passport for the Buenos Aires to Colonia ferry?
Yes, it is an international crossing between Argentina and Uruguay, and passport control is handled at the ferry terminal before boarding.
Is the Rio de Janeiro to Niterói ferry worth taking as a tourist?
Yes — it is cheap, frequent and offers one of the best views of Rio's skyline and Sugarloaf Mountain from the water, in addition to being a genuine part of the city's commuter network.
How do I get to Ilha Grande?
By ferry or speedboat from Angra dos Reis or Conceição de Jacareí, both reachable by bus from Rio de Janeiro; there is no road or bridge to the island.
Are there ferries between Brazil and Argentina directly?
Not as a regular passenger service — the practical River Plate crossings run between Argentina and Uruguay, not Brazil. Travellers moving between Brazil and Argentina overland generally do so by long-distance bus or by air, since the countries do not share a short, ferry-friendly stretch of coast in the way Buenos Aires and Uruguay do.
Sources and further reading:
- Buquebus (buquebus.com) and Colonia Express (coloniaexpress.com) for River Plate crossings.
- Related guide: our Rio to Paraty guide for Brazil's Costa Verde.
- Our guide to coaches in South America for onward overland travel.