The most golf birdies in 12 hours is 67, achieved by Geno Bonnalie (USA) at Lewiston Country Club in Lewiston, Idaho, USA, on 27 June 2011.

Geno achieved the following amount of birdies and eagles between 07:45 – 19:34 between round 5 and round 18 of his record for the “Most holes of golf played in a week” and “Most birdies made in a seven days”.

Round 5 – 4 birdies
Round 6 – 6 birdies
Round 7 – 6 birdies
Round 8 – 6 birdies
Round 9 – 4 birdies
Round 10 – 4 birdies
Round 11 – 4 birdies
Round 12 – 6 birdies
Round 13 – 5 birdies
Round 14 – 2 birdies
Round 15 – 2 birdies
Round 16 – 9 birdies
Round 17 – 4 birdies
Round 18 – 5 birdies