Where to obtain a credencial

Generally you can get a credencial at pilgrims' offices, albergues, churches, chapels, police stations, from the Guardia Civil, or sometimes at town halls.

If you have to start the Camino without an official credencial, just make sure to collect stamps on a piece of paper. Later on, having bought a credencial somewhere on the way, you can attach this piece of paper to it.

Here is a list of places where you can obtain a credencial:

Lisbon Igreja dos Mártires (Rua Garrett, 120)
Coimbra Igreja da Rainha Santa Isabel
Porto Sé, Associação dos Amigos dos Caminhos de Santiago (Rua das Flores)
Tui Catedral