The pass works on all the, city buses, known as “Corredores”. These buses are mostly grey with color-coded accents, and cover Lima’s main arteries. There are also buses on the outskirts that feed into these main routes, called Corredores complementarios, although chances are you won’t find yourself hopping on those.
You can also use it on the Metropolitano, the express bus that runs down the middle of the Via Expresa freeway. With the Lima Pass card, you can easily go from Barranco to Downtown Lima for less than a dollar.
The Lima Pass card doesn’t work on any of the private buses. These are the ones you’ll see on side streets and the main roads that aren’t served by the city’s buses. If you see a guy leaning out of the door yelling, then your card won’t work there.