Aquatic Park is the waterfront area just to the west of Fisherman's Wharf. On a sunny day we found it a great place to have a walk by the bay and enjoy the views out to Alcatraz and of the Golden Gate Bridge. There is a long pier that you can walk along which is a great vantage point for some photos of the aforementioned sights.
You will also see the National Maritime Museum which sits by the bay. This glistening white Art Deco building is very impressive looking, and is shaped like a luxury ocean liner. Renovations were happening when we visited so we couldn't venture inside, but still enjoyed photographing the exterior.