Between January and April, hundreds of gray whales migrate along the coast; the rest of the year humpback and blue whales feed offshore at the Farallon Islands. The best place to watch them from shore is Point Reyes, in Marin County.
For a better view, head out on a whale-watching trip. Seas around San Francisco can be rough, so pack motion-sickness tablets. You should also dress warmly, wear sunscreen, and pack rain gear and sunglasses; binoculars come in handy, too. Tour companies don't provide meals or snacks, so bring your own lunch and water. Make reservations at least a week in advance. Most trips last a full day.
California Whale Adventures (415/760-8613. www.californiawhaleadventures.com) has year-round whale-watching trips ($95) Friday through Sunday. In October, you can take a great white shark tour, and seabird tours run July through October; these tours cost $150 per person and are operated on weekends only. All trips leave from Fisherman's Wharf. The Oceanic Society (415/474-3385. www.oceanicsociety.org) operates year-round whale-watching excursions ($80 Friday, $85 weekends) with top-notch interpretation; in winter they also run half-day trips ($40 Friday, $45 weekends) from Bodega Bay and Half Moon Bay. The society also has a whale-watching hotline (415/474-0488) and publishes the excellent Oceanic Society Field Guide to the Gray Whale. Most trips leave from the San Francisco Yacht Harbor, outside the harbormaster's office in the Marina district.