From one of the Via Algarviana website:
The Via Algarviana starts at the frontier between Spain and Portugal, in Alcoutim, and is the most impressive walking trail in southern Europe.
The trail starts in Alcoutim and winds it way across the Algarve, taking in places such as Vaqueiros, Messines, Monchique until it finally ends in Vila do Bispo. It is now fully signposted with a range of equipment, including poles and direction arrows, informative arrows and interpretation panels.
More information on the trail, including maps and places on interest can be found from the Via Algarviana official site.
The Aljezur Camara has recently announced the addition of a new section of the Via Algarviana from Marmalete to Aljezur. There will also be an additional trail from Vila do Bispo to Santiago da Cacém.