Lee is in a big group on five-under, a shot back from the leading quartet of Moriya Jutanugarn, Danielle Kang, Caroline Masson and Amy Olson.

It continues a good stretch of form for Thai native Jutanugarn, who won for the first time in six years on the circuit last month in Los Angeles.

"What I feel is more relaxed now," she said. "And, of course I like looking forward for my next one."

Olson, meanwhile, is hoping to extend the LPGA Tour's streak of having a new winner in each of its 12 tournaments this year.

She was at her best in the opening round on the front nine, closing it with four birdies in a six-hole stretch.

Even if she doesn't hold on to win the tournament, Olson is on pace to have her best year on the LPGA Tour.

She is No. 39 on the money list after finishing 97th, 119th, 81st and 80th in her first four years.

Australians Rebecca Artis and Su Oh are both in a tie for 15th on three-under, while Katherine Kirk and Sarah Jane Smith both shot one-under.

Hannah Green is two over the card.