The tournament is split over three courses -- the Old Course, Kingsbarns Golf Links and Carnoustie -- for the first three days. The final round is contested at St. Andrews.
Hoey and Brier played St. Andrews Thursday while Cabrera-Bello and Oosthuizen were on Kingsbarns. Marc Warren, one of six players tied at 5-under, had the day's low round at Carnoustie. Two-time defending champion Martin Kaymer is among the 11 players at 4-under.
Hoey opened his round with two birdies and made the turn at 4-under. He had back-to-back bogeys at Nos. 11-12 but answered with back-to-back birdies on the next two holes. The eagle at 18 got him a share of the lead.
Brier had eight birdies only to have a double-bogey 6 at No. 16 pull him back.
Cabrera-Bello got going with an eagle 3 at Kingsbarns' third hole. He added six birdies against one bogey before a bogey at the 18th hole dropped him into the tie for first.
Oosthuizen was 6-under before his long bogey of the day came at the 17th hole. A birdie at 18 put him in the lead.