Underdogs Public Art Store: Tours by appointment, from $34 to $168 per person, depending on size of group and method of transportation. Tours, which include a map, last three hours with an option to customize. Self-guided street-art maps cost $4.50 (under-dogs.net).
Lisbon Street Art Tours: Summer tours on Sunday and Wednesday, reservations required. Payment on donation basis; $12-$17 suggested (facebook.com/lisbonstreetarttours).
Lisbon Destination Tours: The company's street art tour runs throughout the week, reservations required; $23.50 per person for a three-hour tour (lisbondestinationtours.com/tours/street-art-tour).
More information: golisbon.com.