The glass-bottom boat tour has been running from Avalon harbour since the 1890s, making it one of the oldest continually operating tourist attractions in California. The boats cross over the kelp forests and rocky reefs that ring the island, with a glass panel in the hull allowing passengers to look directly down into the underwater garden below. In good light the water is blue-green and the kelp forest extends in all directions.
The tour is 45 minutes and runs multiple times daily, weather permitting. It is perfectly suited to visitors who want a close look at the marine environment without getting wet, including those travelling with young children. The commentary aboard is generally good and covers both the marine biology and the history of tourism on the island.