Magdalena Island is a small, uninhabited island in the Strait of Magellan, northeast of Punta Arenas in Chilean Patagonia. It forms part of the Magdalena Island National Park, together with nearby Marta Island, and is best known for its large colony of Magellanic penguins. The island consists largely of low, windswept terrain covered with grasses and other hardy vegetation, surrounded by cold waters and exposed to the strong weather of the strait. Its isolation and protected status have allowed it to remain an important refuge for seabirds and marine wildlife.

The island has a small but distinctive human history linked to navigation through the Strait of Magellan. A lighthouse stands near the center of the island and continues to serve as a recognizable landmark for vessels using the strait. The Faro Isla Magdalena, constructed in a traditional lighthouse style, also contains interpretive material about the island and its maritime setting. The island is managed as a protected area, and access is regulated to reduce disturbance to wildlife. There are no permanent residents, roads, or conventional settlements on the island.

Magellanic penguins are the principal attraction of Magdalena Island, with thousands nesting across the island during the breeding season. A marked walking trail leads from the landing area toward the lighthouse and passes through areas where penguins dig burrows and move between nesting sites and the shore. Visitors are required to remain on designated paths and keep an appropriate distance from the birds. Other species found around the island and surrounding waters include cormorants, skuas, southern gulls, and other seabirds. Marta Island nearby supports colonies of South American sea lions.