The mountain at the foot of which lies the famous Hálsanefshellir cave, from where you can enjoy stunning views of the Dyrhólaey rock arch, the renowned Reynisfjara beach, and the town of Vík, is also a mountain whose edges serve as a summer nesting site for numerous puffins. When observing and approaching puffins, exercise increased caution (unlike you, they have wings!!).
If you don’t have an extreme quad bike (with tires at least 38 inches), you’ll need to hike up Mount Reynisfjall on foot. From the parking lot (GPS: 63.418608, -19.013634), it will be about an hour’s walk, which is somewhat challenging.