ACTV runs the Venice area’s land buses as well as the water buses. You won’t use buses unless you’re staying on the Lido, or in Mestre on the mainland. From the Lido, you’ll take a vaporetto from Lido-Santa Maria Elisabetto to reach Venice proper. From Mestre, on the other hand, many bus services cross the bridge to Venice’s transport hub at Piazzale Roma, from where you can pick up avaporetto.
Passes for vaporetti are also valid on buses. They should be bought at tabacchi (tobacconists’), major bus stops or from windows or machines in Piazzale Roma before boarding the bus.