At 585 sq km, Santiago Island is pretty large by Galapagos standards. It’s also relatively high: climbing to the top of the shield volcano will bring you to a height 907 m above sea level, with commanding views not only of Santiago but also of the nearby islands in the archipelago.
Puerto Egas, the bay on the western side of Santiago, has a long lava shoreline with numerous curious rock formations. Sally lightfoot crab swim in the rock pools, and sea lion and marine iguana bask on the rocks and sand. There’s some good snorkeling here, too, and you can see plenty of tropical fish in the clear bay waters.
Turtle come to Sullivan Bay to nest, and fur seal come ashore here, too. Scrambling over the rocks gives you a good vantage point, and you might well be able to see the dolphin and shark which come close to the island. In the skies, there are Galapagos hawk, plus flamingo and Darwin finch.