Visits to the Onelli Glacier are usually part of a longer cruise of Lago Argentino that includes the Upsala and Spegazzini glaciers as well. The Onelli Glacier is currently receding, like all others in the area, other than Perito Moreno, and visitors witness the extraordinary glacier by boat, navigating the milky-blue waters of Lago Argentino.
The glacier in particular does not feed into Lago Argentino proper, but instead drains into Onelli Lake, which is accessible via a walk through a native beech forest from Onelli Bay. The lake offers views of three glaciers: Bolados, Agassiz and Onelli, which is eight miles long, covering 32 square miles.
Upsala glacier is famous for its activity and the Spegazzini for its towering height (nearly 45 feet), but Onelli has its own charm. Because visitors approach the glacier by foot (via a mile-long walk), there is a different sense of Patagonia here. You can see, hear and smell the forest atmosphere in the same way explorer Clemente Onelli did before the glacier was named after him. He found himself visiting the area in the 1880s to determine the precise location of the Chile-Argentina border.