Reynisfjara is a scenic black sand beach that has been ranked as one of ten most beautiful non-tropical beaches in the world. The power of the waves can be enormous, and great care must be taken not to go too close to the waterfront. Sneaker waves, i.e., disproportionately large waves, can sweep the beach without warning. Unfortunately, this has resulted in fatalities in the recent past, despite warning signs and recommendations from guides and tour operators.

Reynisfjara and surroundings offer a variety of basalt rock formations, e.g., tuff, columns and pillows. Basalt pillows and columns are formed under high pressure where the molten magma cools and hardens in the core of the volcano, whereas the softer tuff basalt is found on the outer side of the volcanos. The basalt formations result from eruptions on the ocean floor or under glaciers.