Lake Izabal (Spanish pronunciation: [isaˈβal]), also known as the Golfo Dulce, is the largest lake in Guatemala with a surface area of 589.6 km2 (145,700 acres; 227.6 sq mi) and a maximum depth of 18 m (59 ft).

The well preserved colonial Castillo de San Felipe de Lara guarded this lake against pirate attacks, and there are some ancient sunken ships nearby.

It is home to several species including the Manatee, Jaguar, Spider Monkey, Blue-eye cichlids, and Howler Monkey, and is a popular place for birdwatching.

There are many indigenous communities surrounding the lake, namely the Mayas Q'eqchi'.

The Castle of San Felipe de Lara, constructed in 1652 in honor of judge Antonio Lara Mangravo, was built to protect the region from pirates.