Maranhenses has its unique physical features that you can find nowhere else. The best way to reach the park is to get to São Luís, from there it takes about four hours drive to Lençois Maranhenses National Park. Flights from all over the county land regularly to Sao Luis and once you are in the city, almost every pousada, hotel or hostel will be able to arrange a transfer for you.
There are three main points of entry. Barreirinhas is the most common one. Santo Amaro and Atins are on opposite sides of the park and are much quite little coastal towns.
After about 3 hours driving from Sao Luis I arrived to town Barreirinhas. Most of the people get tours from Barreirinhas to Maranhenses National Park, however I totally recommend to leave the car in Barreirinhas and take a boat to Atins. There is no driving way to Atins but there are a few companies operating small boats, it takes about an hour.
In Atins try to rent a 4*4 with a driver. In the town center there are a few tourist agencies, skip them, they ask for ridiculous prices. I recommend to stay in the family driven hotel I have stayed, Paraiso dos Ventos, their owners are so helpful, they organized for me a jeep with a driver for a reasonable price. Do not try to drive yourself, you can find out the GPS location of the lagoons but its hard to drive in sandy conditions you can easily got stuck w/o knowledge of the landscape.
Maranhenses gets too much rain at certain times of the year to be categorised as a desert. The rainwater gathers between the dunes and form lakes. The rock layer under the water is so hard that it forms a water resistant layer. The result is midnight blue lakes offset by brilliant white dunes.
Don`t forget your swimming costume. After trekking across the dunes, you must throw yourself into the clear rain water.
If you have enough time, in Barreirinhas they also organise tours for a week to explore the national park on foot. You can also hire horses or quadbikes.
The Maranhenses is far less known and visited compared to other big natural wonders like Iguazu Falls, but to me, it is much extraordinary experience and was definitely highlight of my trip to Brasil.
Here is the youtube video fo the trip: