When thinking of whale watching in and around San Diego you should really consider greater Southern California.  Many providers offer whale watching only during the traditional whale watching season which is from January thru April, however; there are several whale watching providers that provide whale watching year round.  These year round whale watching providers typically concentrate on whale watching as their primary business activity as opposed to tyring to fill a void during their off season. What you get from these year round providers may be worth the extra travel time and that is up to each individual.  The perks of these year round providers are ships designed specially for whale watching, highly trained staff, and a more focused experience.   Here are several year round whale watching providers:

Newport Landing Whale Watching-They are located in Newport Harbor about 45 minutes from downtown San Diego.  Their website is  http://www.newportwhales.com/ .  With a 96% success rate they take their whale watching very seriously. Grey whales in the winter/spring and giant blue whales in the summer/fall.

Condor Cruises-They are located in Santa Barbara which is about 2 1/2 hours from San Diego.  They travel to the famous Channel Islands and also have a high success rate with viewings. Their website is http://www.condorcruises.com/ . Sightings can include grey whales, blue whales, humpback whales, and others.

Harbor Breeze Cruises-Located in Long Beach which is about 1 1/2 hours from San Diego.  They offer year round whale watching and are located next to the Aquarium Of The Pacific.  Their website is http://www.2seewhales.com/ . 

Unfortunately San Diego does not seem to have any year round whale watching providers although you can rent your own boat with Seaforth Boat Rental .

San Diego does have seasonal whale watching providers such as:

Point Loma Sportfishing - http://www.pointlomasportfishing.com/

&

Hornblower Cruises- http://www.hornblower.com/

 For those considering shore bound whale watching a great shore based location is the Cabrillo National Monument.  The cost to enter the park is $5 per vehicle.  The Cabrillo National Monument is the birth place of whale watching and still provides good opportunities to see grey whales.  Make sure to bring your binoculars. 

Update April 26 Blue Whales are starting to show in the Catalina Channel.

Update July 11 2009  Multiple Blue Whales Each Cruise Common