Bay Area Seals
Here's a collection of places I've had luck seeing seals in the bay area. They are arranged going North to South along the coast.
Moss Beach - Harbor Seals
Specifically Fitzgerald Regional Preserve. In the spring, there is a small breeding colony that hauls out on the beach.
Pillar Point - Harbor Seals
Some seals can be viewed at low tide way out in the tidepools.
Año Nuevo State Park - Elephant Seals
Large breeding colony. Best time to see them is January or February, but some small population is present at all times. Tickets for the winter guided tours sell out very quickly, but they have day-of tickets available. Best to get there around 10:00-11:00 AM. It's easily one of the best wildlife experiences I've had in the U.S.!
Monterey Municipal Beach - Harbor Seals
The vast majority of animals here were sea lions, but there is some good views from the trail of harbor seals in the harbor sunning on rocks.