There are eight hidden Burner Phones scattered throughout the game in Watch Dogs, and when you find them you’ll unlock the Vespid LE bonus vehicle.
I guess technically there are only really seven hidden burner phones, because one is given to you automatically during Act 1.
Burner Phone 1 Location
Located in the May City Locker Room, automatically received during a mission in Act 1.
Burner Phone 2 Location
Found in a blue shed near the Marina on the southern edge of downtown Pawnee.
Burner Phone 3 Location
Located on the southeast edge of Pawnee. Look for a building with a big MOTEL sign on top of it. Climb to the roof of this building and you’ll see it near the letter L.
Burner Phone 4 Location
Find the trailer park in southern Pawnee, and look for the classiest trailer you can find.. meaning the one with two patio chairs and a table on it. Climb up there and you’ll see it sitting on a railing.
Burner Phone 5 Location
On the second floor inside of a warehouse on the east end of Brandon Docks. You’ll find the phone on a desk next to a computer.
Burner Phone 6 Location
A little south of Burner Phone 4 on the east end of Brandon Docks. You’ll find it on the second floor of another warehouse sitting on a nasty mattress.
Burner Phone 7 Location
You’ll find this one in the Rosse-Freemont housing area, which is easier to access mid-way through Act 4. Look on the second story of one of the buildings there and you’ll find it sitting on a ledge near a plywood plank.
Burner Phone 8 Location
Look in the homeless camp in the southwest corner of The Loop. You’ll find it on another nasty mattress.