Lake Arenal

Lake Arenal is a large reservoir in northwestern Costa Rica spanning parts of the Guanacaste and Alajuela regions, formed when the Arenal Dam was completed in 1979. It is one of the country’s largest inland waterbodies and an important hydroelectric resource.

The lake is used for a range of water-based recreation including windsurfing, sailing, fishing and boating, with marinas and launch points concentrated on accessible shores; the reservoir also provides habitat for local birdlife. Views of the nearby Arenal Volcano are a frequent draw from vantage points on the lake shore.

The dam project enlarged the preexisting lake and reshaped local transport and land use, while hydroelectric facilities at the dam feed power into the national grid. Tourism infrastructure developed along the lake’s accessible shores, especially near the town of Tilarán.

Lake Arenal lies in the Tilarán mountain area of northwestern Costa Rica, between the Arenal volcano complex and the lowlands of Guanacaste.

• Size and origin: The reservoir covers roughly 85 square kilometers and was formed when the Arenal Dam was completed in 1979.
• Wind conditions: Consistently windy conditions on much of the lake make it one of Costa Rica's principal sites for windsurfing and other sailing sports, especially during the dry season.

What to See #

• Arenal Dam: A concrete hydroelectric dam at the southern end of the reservoir created the expanded lake in 1979 and supplies electricity to Costa Rica's national grid.
• Recreation and marinas: The lake's northern and eastern shores host marinas and launch points used for windsurfing, fishing and motor boating, with visitor facilities concentrated near the town of Tilarán.