What a great way to spend the day! Just a 12 minute ferry ride from Tiberon. We hiked Perimeter Road around the island, about 5 miles. It's paved and mostly flat with panoramic views of the entire San Francisco Bay. We brought our binoculars and took our time. We saw some deer, hawks, harbor seals, lots of birds, and a cayote. There are many benches and picnic tables, water taps, and some restrooms along this road. Pack a lunch, there are no concessions. At one point, my boyfriend hiked a trail up to the peak and we met back up at the Immigration Station. The island has a lot of history we didn't know about. We would like to go back and explore some of the places we didn't get to explore today.