Only official tourist trips in 4x4 coaches penetrate the reserve but productive bird watching is possible from a car along the rough agricultural tracks and pot holed roads  on the east side of the Guadalquivir.
From Bonanza, continue ahead through the woodland on  a rough track until a T junction, where you turn left. At a small works, a track leads left to Bonanza salines or right on tarmac along the river (parts of the roads are so bad 4x4s take to the dirt in preference).
From Trebujena, at a small roundabout in the centre there is a sign for Guadalquivir, follow it, forking left once, just outside the village. (This is the best route for non 4x4s). As you approach the river, turn right and keep forking left where possible, to reach the area of rice fields.
From Los Palacios y Villafranca,   find the bridge (on back streets) at the west of the town by a building with tall storage tanks and cross into the cotton and then rice fields. (This part of the area mostly has agricultural dirt tracks, some of these are fine in a car, others are in part impassable without 4 wheel drive). Follow the metalled road out of the town and at a junction near a lone industrial building, turn sharp right (north) for a productive stretch of track, when the surface changes to a different clay like material DO NOT PROCEED in non 4x4s.