More than 250 riders, including 2016 Downhill World Champions Danny Hart and Rachel Atherton, will be competing.
This year, Salisbury-born Atherton is seeking a 15th successive World Cup circuit win.
The Fort William competition forms the third stage of the UCI World Cup Downhill championships.
Held at Nevis Range, the weekend of events usually draws a crowd of almost 20,000 people.
Atherton won the women's final for the ninth consecutive time last year, and South African Greg Minaar won the men's final.
Final preparations are being made for this weekend's staging of the Fort William Mountain Bike World Cup and Buff 4X Pro Tour.