San Francisco is a less busy port than those in southern California. However, it still operates year-round and offers a nice variety of cruise itineraries.
Alaska (10+ nights) and Mexico (4 to 10+ nights) are the two most common itineraries, with Hawaii taking the bronze (14+ nights).
On top of these options, there are periodic Panama Canal cruises that end on the US east coast.
Finally, befitting the city’s stature, world cruises and segments are often available from here.