B&B Casa Gottardi is located very close to the Rialto Station on the Grand Canal. This means you have two very good options. You can take the Alilaguna Water Bus, Orange Line, directly from the airport and simply get off at the Rialto Station. Your B&B is just a few minutes walk from there. Or, you can take a bus or taxi from the airport to Piazzale Roma and hop on the vaporetto, which is the public transportation water bus, and get off at the same Rialto Station or even the San Silvestro Station. With the Rialto Station you have to cross over the Rialto bridge while the San Silvestro Station is on the opposite side of the canal where your B&B is located. The cost for the Alilaguna service is 27 euro round-trip. The cost for the bus/vaporetto is about the same with a taxi perhaps costing a few extra euro. You can also buy a multi-day card for use with both the land buses and the vaporetto, which may save you some money if you are staying for a few days and plan on using the public transportation in Venice.