A five mile guided hike from Samuel P. Taylor State Park to the Leo T Cronin Fish Viewing Area along Lagunitas Creek and back again to spot spawning Coho Salmon. The hike was a program offered by Turtle Island and the specific route will vary based on where the salmon are currently active. Having done this once I think I could spot them again without assistance but it's well worth donating to get the full naturalist led experience.
Round Top is a remnant of a 10 million year old volcano, tipped over by tectonic activity. It's pretty high at 1,763 feet. Unfortunately the peak is privately owned so you can't go right to the top but there is a 2.5 mile loop around the peak. You get views out to Mount Tam, Mount Diablo and even the Sierras and an occasional glimpse of the bay. The drive up is also spectacular.
San Bruno Mountain State Park has outstanding views of San Francisco, the Pacific out to the Farallon Islands and much of the bay. We did the three mile summit loop (the wrong way round, San Bruno pros do it counter-clockwise).
Pinnacles is the newest National Park which features various hikes to Talus Caves (formed by rockfalls into a valley) which are fun to scramble through as long as you don't think about the formation process while you do it.
Devil's Slide Trail used to be one of the most scenic stretches of Highway 1. It was hard to enjoy though while you were trying not to crash and die. Now it's a leisurely stroll with magnificent views and well worth a visit.
Coastal redwoods at Armstrong Redwoods State Natural Reserve. Parson Jones is over 310 feet high, Colonel Armstrong over 1,400 years old.
Salt Point State Park on the Sonoma coast. Stunning views, plentiful seals and some cool tide pools (although the rocks on the way down are like greased butter). Apparently the sandstone from Salt Point was used to pave San Francisco which goes a long way to explain the state of the streets...
Like the Internet, The Wave Organ is a series of tubes. Unlike the Internet it groans at you in different ways as the tide comes in and out. It’s also a nice walk on a blustery day with great views around the bay and back over to the Marina.
Hike starts at: 37.806707, -122.446921.
Hike starts at: 37.62864, -122.463666.