As a vegetarian, I found restaurant meals rather challenging. Where there was little or no choice, it was problematical. For example, on one occasion the first course at the only restaurant in town was green beans (habichuelas) which arrived mixed with large amounts of ham (jamon). This was my first restaurant meal in Galicia, where the albergues have kitchens, but no pots or dishes. You can say "No como carne" - "I don't eat meat" but they do not always categorize as meat what we would. Try to specify: "Soy vegetariano/a (masculine/feminine form), no como carne" when you inquire about the menu and before you order anything. It helps if you are willing to eat fish in a pinch, as I am. Plan ahead to cook for yourself where there is a kitchen. Bear in mind that an apparently innocuous dish, such as ensalada mixta (mixed salad) is likely to have large amounts of tuna in it. You can say "Sin atun (tuna) por favor" (Without tuna, please). Where there are vegetarian restaurants, they are likely to be at least as expensive as regular restaurants. Albergues which supply meals for pilgrims sometimes understand what you mean by vegetarian and sometimes do not. For example, if most of the chorizo (sausage) has been picked out of the communal dish, they may consider it perfectly fine for a vegetarian. Plan ahead and keep your sense of humour.