Short trail along the riverside of Ria de Alvor. 12 easy caches, where the first 4 are along the Biodiversity Station trail and the remaing are at Alvor Estuary. If you start from Alvor it's appropriate to begin with te cache "O Cantinho Encantado [Alvor/Portimão]" and continue from there.
The total distance is 3.5 km (one way), it's not suitable for strollers and can be slippery when it's rain.
Don't forget to read the information boards along the trail. For more information:
https://www.alltrails.com/trail/portugal/faro/trilho-da-estacao-da-biodiversidade-de-alvor-ebio
Happy caching.