Laguna Beach does not have any harbor or boating facilities wihtin it's city limits, so you can choose between Long Beach, Newport Beach and Dana Point. Newport Beach borders Laguna from the north and Dana Point borders Laguna from the south. Here are some companies that offer  whale watching in and around Laguna Beach year round:

In Newport Beach

Newport Landing Whale Watching

Davey's Locker Whale Watching

Ocean Explorer Cruises 

In Dana Point

Capt. Dave's Dolphin & Whale Safari

Dana Point Whale Watching

Dana Wharf  Whale Watching 

In Long Beach

Harbor Breeze Cruises

Whale watching has become a year round acitivity with the emergence  of the blue whales during the summer months.  In the past the majority of whale watching in the Laguna Beach area took place from December through April which coincides with the gray whale migration.  The migration brings thousands of gray whales along the southern California coastline and down to Baja to breed and then brings them back again to their summer feeding grounds.

Whale watching is a great activity for the whole family and along with viewing over a half dozen whale species, several species of dolphin, sea lions, and many other marine species can be viewed on each trip.