One way to travel to northern Spain is by booking a Smithsonian Tour. These guided tours are 12 days long and take you through five cities and include transportation from the United States.
Take a ferry or boat from London or France to northern Spain. One service that takes many trips daily is Brittany Ferries.
Santiago International Airport is in northern Spain, and budget airlines make a couple of stops daily. Ryanair arrives every afternoon as well as EasyJet. If you are looking to travel on major airlines, try Iberia, Spanair or Air Europa, all of which fly into Santiago airport.
Eurolines runs across Europe and makes frequent stops in Galicia, Madrid and Cantabria from most major cities in Europe.
If you are traveling from other parts of Spain, Renfe trains have a station in Galicia. If you want to travel outside of Galicia, buses, car rentals and outbound trains are available.