The Key Summit Trail, a popular day walk near Milford Sound in New Zealand's Fiordland National Park, offers stunning panoramic views of mountains, alpine lakes, and forests. It's a moderate, well-maintained track, accessible to most active individuals but not wheelchair-friendly, typically taking 3-4 hours return from The Divide trailhead. While easily undertaken solo due to its clear signage and popularity, guided options are also available. The trail is best enjoyed from late spring to early autumn (November-April) as winter conditions often bring snow, making it more challenging and potentially hazardous; always check Department of Conservation (DOC) alerts. There is no direct cost for the trail itself, though transport to the trailhead (e.g., shuttle from Te Anau or Queenstown) will incur expenses, usually NZD 50-100+. Visitors should carry water, snacks, and wear appropriate clothing for rapidly changing alpine weather.