Hiking is the most popular activity in the park. The main starting points are from the park's entrance or from radio road at the mountain's summit. Various neighborhood access points including Crocker Road and Charter Street also provide good starting points.The park is home to a wide variety of birds and animals as well as several endangered plant and butterfly species. The park has family picnic sites near the park entrance. Tables, barbecue pits, drinking water and a restroom are also available. All facilities are accessible to people of all abilities. Eight trails make up the trail system in San Bruno Mountain Park: Eucalyptus Loop (1.08 miles), Bog Trail (.77 miles), Old Guadalupe Trail (.8 miles), Summit Loop Trail (3.13 miles), Saddle Loop Trail (2.1 miles), Dairy Ravine Trail (.43 miles), Ridge Trail (2.43 miles), and Old Ranch Road Trail (.71 miles). Some trails are restricted to hikers only.
After entering through Crocker Road,I spent around 3 hours walking in the park- Bog Trail & Old Gaudulupe Trail. I had my newly acquired Can Powershot camera with me and several exotic pictures of flora in the park. Being a working day the park was largely deserted barring a few Senior Citizens.
Eucalyptus trees(imported) & a large overgrowth of ivy were posing a major threat to growth of native plants & wild life. I was cautioned to look out for mountain lions but fortunately did not encounter one.