Costa Rica Arenal geological zone is the center of the Northern San Carlos Plains and includes the Arenal volcano and lake. Arenal Volcano is active and provides exciting red lava eruptions approximately every forty-seven minutes.

The region has many hot water springs generated by the volcano. Arenal Lake has excellent brown bass fishing and is world renowned for windsurfing.

The area is noted for its European style spas offering mud baths, body massage and healing waters. Arenal is dotted with excellent hotel accommodations, often associated with the spas.