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 ($5 for the day pass and $2 for a reloadable Compass card) 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).

Another option is getting an all day regional pass for $12.  This can be loaded onto the Compass Card and allows you to use the buses, trolleys, trains, Amtrack, and COASTER, SPRINTER, BREEZE, and other local means of transportation as far north as Riverside, and as far south as Chula Vista.  You can go from the coast to as far east as Escondido.  The Compass cards can be loaded at trolley and train stations, as well as directly on the bus, and can be purchased in advance and activated in the future by initiating use.

 The best feature of the public transportation is that when you are at a bus stop it is clearly marked with the buses that leave from there.  You can text the listed stop id number to 46687 and see what time the next bus is due to arrive.  This helps aleviate the need to carry around a bunch of schedules.  The buses have great connections and minimal downtime.  Renting a car is not necessary to get to many cities.

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.