Three-under par opening rounds of 69 have West Australians Joshua Greer and Karl Vilips and New South Wales' Harrison Crowe four behind leader Bo Jin of China at the Asia-Pacific Amateur Championship at Amata Spring Country Club in Thailand.

Preferred lies were used throughout the day due to overnight thunder storms and the three Australians taking advantage of that ruling, as well as the softer greens, to put themselves into a share of 13th place.

Greer, who only recently returned to golf from a fractured wrist, found the going tough early despite the favourable conditions. He was one-over par at the halfway mark of his round courtesy of two bogeys and a sole birdie on the front nine.

From then on, the Joondalup Country Club member found his groove with a hat-trick of birdies at the 10th, 11th and 12th holes, and the third of that trio - at a 382-yard par-4 - was his favourite.

"I would say the third birdie (stood out), so the 12th," Greer said. "I hit to two foot and that got me going after making two sort of 8‑footers for birdie and then hitting it close there, that was good."

Greer made another birdie at the par-5 15th, but he followed it up with a bogey at the very next hole, before saving his best for last.

"It was 50 feet. I was just hitting and hoping and it went in," he said of his birdie putt at the 18th.

"They moved the tees way forward, so I was hitting as hard as I could, trying to leave myself a shot in. But I left it in the rough, hit a flyer that went miles but holed the putt."

NSW Open champion Crowe began his day from the 10th tee and produced a consistent opening nine to reach the turn bogey free at one-under par.

His scorecard became far more colourful on the front nine as back-to-back birdies at the first and second holes pushed Crowe up the leaderboard before a bogey at the fourth disrupted his momentum.

The same pattern happened again with successive birdies at the sixth and seventh, but he closed out his round with a bogey at the last.

Stanford University student Vilips appeared as if he was going to make an afternoon charge for the lead after he was bogey free four-under par through 12 holes.

His first blemish of the day arrived at 210-yard par-3 13th in the form of a bogey, but despite making another two birdies for the round, a double bogey at the 16th ultimately stunted Vilips' progress.

Australian Amateur champion Connor McKinney was the only other Australian to break par in the first round with his one-under 71 that included four birdies.

West Australian Hayden Hopewell and two-time Australian Junior Amateur champion Jeffrey Guan produced even-par rounds, while Victorian Lukas Michel ended the day six-over.

Follow the scores