Reserva Natural do Sapal de Castro Marim e Vila Real do San Antonio, Portugal

Castro Marim reserve
The reserve as seen from near the Centre

Near to the Spanish border, this is a smallish (by Portuguese standards) coastal nature reserve of most interest to birdwatchers, although there are some interesting salt-marsh plants there too.


The Reserva Natural do Sapal de Castro Marim is located near to Villa Real de Santo Antonio on the eastern side of the Algarve, just a few minutes drive from the Portuguese-Spanish border and the Rio Guadiana river, and is well signposted from the main roads. There is ample car parking at the reserve, and a walk of some 12km around the saltpans for those who like to explore.

General Description of the Castro Marim Reserve

The Reserve covers just over 2,000 hectares on the estuary of the River Guadiana and has an Information and Educational Centre that we have yet to find open. This is the most recent of the nature reserves and parks to be designated in the Algarve, and it came into existence in 1975. Although much of the reserve is still functioning as a salt production operation, the mudflats and lagoons are of immense importance to resident, visiting and migratory birds. Many interesting saltmarsh plants also thrive within the confines of the reserve.

The Plants of Castro Marim

Water Plantain
Water Plantain (above) thrives at this reserve

Early spring is the best time to visit Castro Marim if you want to see the special plants that are able to survive the inhospitable environment of saltpans, salt-marsh and the brackish-water mudflats in the estuary of the River Guadiana. The pretty Water Plantain, with its three-petalled flowers, is plentiful in the reserve.

Birds at Castro Marim

Black-winged Stilt
A Black-winged Stilt foraging along the estuary banks

This reserve is a wintering ground, and one of the best places to see, the Greater Flamingo along with Avocets, Spoonbills, Black-winged Stilts and many species of ducks. There are also many storks nests in trees on the reserve - something of a novelty, as these birds are most often seen nesting on chimneys and electricity pylons throughout the Algarve!

Terns are well represented here including, in the winter, the world’s largest: the Caspian Tern. Sandwich Terns and  Little Terns nest on the edges of the saltpans; and Black-headed, Black-backed and Yellow–legged Gulls all visit Castro Marim.

More about the Algarve and its wildlife...

Top of page...

Please Help Us: If you have found this information interesting and useful, please consider helping to keep First Nature online by making a small donation towards the web hosting and internet costs.

Any donations over and above the essential running costs will help support the conservation work of Plantlife, the Rivers Trust and charitable botanic gardens - as do author royalties and publisher proceeds from books by Pat and Sue.

© 1995 - 2022 First Nature: a not-for-profit volunteer-run resource

Please help to keep this free resource online...

Terms of use - Privacy policy - Disable cookies - Links policy