Depending upon the area that you will be staying at, transportation can vary. San Diego is quite spread out and walking is not too practical unless you are staying in the downtown area.  For public transit directions you can call (619) 233-3004.  Know ahead of time the address you are at and the address you are going to, as well as the time and date of your trip. For $7 you can get a one day pass for both trollies and busses. Trollies run every 15 mins and most buses every 30 minutes (15 to airport)

If you are staying downtown, then you can easily walk to many wonderful restaurants, night clubs and shops (including Horton Plaza), as well as Seaport Village. The bus & trolley are easy to take from downtown to Balboa Park, the Zoo, and Old Town. Beyond that, plan to be on the bus at least 30 minutes and even up to an hour or more to get other places in San Diego.  Here is a link to a public transit map of downtown San DIego that was accurate as of December 2011 http://www.sdmts.com/images/subregion... .

Taxis are available (see the San Diego: Taxis and Rental Cars page), but can be expensive. Renting a car is highly recommended if you plan to venture beyond the area you are staying.

Luggage storage is available at San Diego Airport luggage storage 619 683 2050. They can collect cases from the cruise ship port at 8.30 am, stored them and delivered them to the airport at 8pm for $30.