The Sancti Petri Marshes are a tidal wetland of about 170 hectares located in Chiclana de la Frontera, within the Bay of Cadiz Natural Park. The Junta de Andalucía describes them as an area of very high ecological value, with critical and vulnerable habitats, and as a key area for resting, feeding and breeding of aquatic birds, as well as fish, crustaceans and mollusks. Its condition as an active marsh means that the landscape changes with the tide, through channels, canals and flooded plains. From the observation points in the surrounding area, an open, horizontal marsh can be seen, with sheets of brackish water, salt marshes and vegetation adapted to the salinity. The area preserves a historic landscape of the bay and stands out for its ornithological interest, especially for waders, gulls and terns. It is also mentioned its integration in the network of protected areas such as ZEPA and Ramsar site, which reinforces its natural relevance. Its interest is not so much panoramic as ecological: here the reading of the wetland, the tide and the avifauna is more important than an elevated viewpoint. The best time to visit is usually the time of greatest bird activity, during migration and wintering, and also at mid or high tide, when the water concentrates the life in the channels and resting places. If it is documented as a nature resource in a guide, it should be mentioned as a protected tidal wetland site, closely linked to the Bay of Cadiz Natural Park and the coastal landscape of Chiclana.
