Motorboats ferry passengers across the Rio Mamoré between Guajará-Mirim and Guayaramerín, Bolivia (R$10, 10 minutes). A minimum of 10 passengers is usually required, but it’s rare to wait more than 30 minutes; the last boats leave an hour or so before sunset. Border formalities are completed on arrival. The port and ticket office in Guajará-Mirim are on Av Beira Rio. There's also a vehicle ferry.