Landfall is the first glimpse of land when you're on a boat. It can also mean the moment your boat touches the shore, like when your kayak makes landfall on a remote island.
If you're traveling at sea, arriving at your destination is landfall. A child paddling a rowboat across a pond makes landfall when she reaches the far shore, and the captain of an ocean liner makes landfall at each remote stop on the route. A sailor might call out, "Landfall!" at the first sight of land on the horizon. The word landfall uses the sense of fall that means "happen."