Your Lencois Maranhenses tour, dunes to sunset.

From above, the Lencois Maranhenses looks like a white sheet thrown across the coast of Maranhao. SETUR-MA, the state tourism office, describes dunes reaching about 50 km inland from more than 70 km of empty beach. From the top of any crest the white ridges seem to run on forever, broken only by water and the occasional patch of green, and in the morning the wind has already wiped yesterday's footprints away.

What sets the place apart is the water. Rains from January to July, says the same office, leave lagoons in blue and green between the ridges, and the tiniest residents, little fish, survive the dry spell as eggs lying dormant under the sand. Few landscapes change so completely with the season. Return in another month and you may not recognize the view.

The country has protected it since a federal decree of 1981, and in 2024 UNESCO inscribed the national park as World Natural Heritage. The federal park authority, ICMBio, measures it at 156,608.16 hectares, of which the day from Barreirinhas shows only the eastern edge. The rest is wilderness reached on foot or by long journeys from the other gateways, which is part of what keeps it so quiet.

Everything here depends on the rain. According to SETUR-MA, the water arrives with the downpours of January to July. On our listing the wet season usually means January to June and the dry one July to December, and the lagoons stay high for about 4 months in an average year.

Visit in the full months and the dunes hold more water than seems possible, deep enough to swim in almost every hollow. Come late in the dry season and many basins are low or empty, though the state tourism office says the largest of them, Lagoa da Gaivota by Santo Amaro, never runs dry. The listing says its tours adapt their routes to the lagoons best suited to the conditions.

The park itself never closes: ICMBio keeps it open to visitors all year round. If your dates are flexible, aim for the months when the water is highest and keep a spare day in Barreirinhas, so a rainy morning only moves your tour rather than cancelling it. A tour moved by a day is a small price for seeing the lagoons at their best.

The listing names a live guide who speaks Portuguese. If you speak none, you will still see every lagoon and the sunset, and a recent guest describes a morning briefing that kept everyone in the loop. A handful of Portuguese words, thank you and good morning among them, goes a long way with a driver. A translation app downloaded for offline use helps too, since signal in the dunes is patchy.

If explanations in English matter to you, you have options. An afternoon at Lagoa Bonita and the high dunes comes with an English, Spanish or Portuguese speaking guide, and the private full day offers those languages and French as well. The private day costs far more than the shared combo day and the Bonita afternoon costs less but leaves out Lagoa Azul, yet for some travelers the explanations are half the experience.

The combo day itself can be arranged for a private or small group. For families or friends traveling together, that means your own vehicle, your own pace and a guide who answers only your questions. Ask the operator for the private price for your party before you book. A private vehicle also makes it easier to linger at a favorite lagoon or leave a crowded one early.