This hiking trail gets its name from the former smaller branch or "old river"; one of the two channels the mouth of the Guadalhorce once split off into. It allows visitors to the Desembocadura del Guadalhorce Natural Park , to not only enjoy a pleasant walk through this unique protected area, but also to discover the environmental and cultural values this place possesses in an urban and civilised environment; a stark contrast to the neighbouring city. This is possibly the most surprising factor to hikers; discovering just how close to houses and large infrastructure an oasis of life is hidden, and all thanks to an easy route which encourages getting close to nature without harming it.

The route shares its starting point and the first 450 metres with the Laguna Grande hiking trail. In this shared part, the Guadalhorce riverbed is visible from a structure built not long ago, on the early 20th century pillars of the old railway bridge that served the now out-of-use Málaga-Fuengirola and Málaga-Coín lines. From here, discover numerous species of birds (depending on the season) such as house martins, swallows, gulls and various ducks, cormorants and even daytime birds of prey, along with views of the river ecosystem and its banks populated with African tamarisk, eucalyptus and reed beds, which will undoubtedly make the walk enjoyable from the beginning. Additionally, from here, the Cerro del Villar s easily located, on the right bank of the river and in front of where the trail begins,. This was an important Phoenician site dated between 800 and 600 BC, whose port opened up into the waters of the Guadalhorce in roughly this very place.

The route runs along a dirt track at a very gentle gradient and is wide enough to comfortably accomodate groups, especially school trips. The first part runs alongside fields of canes that, although not sugarcane, are reminiscent of the appearance this farm once had. The farm was known as "The Island" as it was surrounded by the two old branches of the river and the sea on the southern side, and, in the not-to distant past sugarcane was almost the only crop grown on the land, which was used as raw material in the neighbouring sugar factory, Azucarera Hispania, the last industry of this type in Malaga city centre that continued operating until a few decades ago.

Another aspect which could be of interest is the wide visual area covered from the trail. A look at the landscape from here shows the Neighbouring Sierra de Churriana and Mijas or the Monte de San Antón, the latter being situated in the very city of Málaga, along with more distant peaks and mountains such as Pico Maroma, in Sierra Tejeda, El Santo Pitar, Cerro de la Matanza, Pico Reina or the Lomas de Verdiales in the Montes de Málaga, and even part of the white mountains of the limestone arch, such as the Torcal de Antequera, the Sierras de Chástica, Huma, Prieta and even the Sierra de las Nieves. A good place without a doubt, to understand the concept of "Hoya de Málaga" that applies to the unique location of the city.

Along the route on both sides are a series of tree, shrub or grassland species likely to capture the hiker's attention and interest, with some of them being recently planted after the conditioning works at the mouth of the river Guadalhorce, or the result of subsequent reforestation or introduction tasksefforts. Wild olive trees, holm oaks, acacias, stone pines (very exceptionally Aleppo pines), African tamarisk, white and black hawthorns, mastics, buckthorns, strawberry trees, white poplars, figs, salicornias, rushes, reeds and even cork oaks can be potted along the trail. Increasing little by little along the route, the large conopies of some of these trees causes them to cast areas of shade across the path, which are very welcome in the warmer seasons.

This hiking trail also boasts three wildlife observatories the hiker may visit and rest whilst enjoying seeing the many species that inhabit the observatory, as well as the beach and nearby sea. Then, after walking 780m on the trail, you'll find the "Laguna de la Casilla" observatory; a point where, depending on the time of year, you may see coots, stilts, pochards, egrets, grebes, white-headed ducks, bittern, purple gallinule, bluebirds, nightingales, jackdaws and many others. If lucky, you may surprise very elusive but frequent visitors such as the Montpellier snake, the otter, the mongoose, the weasel or the fox. Bear in mind that that the existence of lagoons and waterlogged areas here is the result of the past gravel pit that existed at the mouth of the river, and the ditches filled with water are today a source of life. Continuing on for another 210 m, leads to the second observatory, the "Old River" given its location right in the bend of the old channel. From this point, close to the beach, you'll start to see species of sea birds linked to the marine environment, such as seagulls with their various species (black-headed, yellow-legged, black-billed or Audouin among others), accompanied by numerous waders and long-legged birds that wade and run along the banks of the old river in search of food.

The last section of the path runs straight to the beach, offering very interesting views of the Malaga Bay as well as the city. The vegetation is reduced to creeping species or those small and samophilous in character (typical of sandy beaches), and here you'll be able to discover sea fennels and poppies, daisies and beach thistles. The trail ends at the Seabird Observatory, a point for rest and entertainment where you can try to identify birds such as the auk, the common blackbird, the plovers or the seagulls.

Please, use the facilities in a responsible and respectful way, being mindful of the local environment and other users, avoiding unfair behaviour in oder to enjoy the space together in accordance with the wonderful environment that welcomes you. Do not enter with animals or that may pose a danger to other people or animals, and bear in mind that dogs must be led by people of legal age, on a lead and you must be carrying identification (if they exceed 20 Kg they must wear a muzzle, harness and non-extensible strap) If you are cycling the trail, do so in a way that does not endanger pedestrians, and in any case please comply with the speed determined by current traffic regulations in the municipality of Málaga.