Leona Maguire and Lauren Walsh began their AIG Women's Open tournaments with level-par 72s at Royal Porthcawl as Japanese duo Eri Okayama and Rio Takeda lead the way on five-under par.
It would be a tale of two nines for Anna Foster however, as she slid down the leaderboard after an error strewn back nine, with four bogeys and a double seeing her shoot a four-over-round of 76.
Maguire started the final major of the season with a bogey at the first with another following at the fourth, but the Cavan woman rolled in a good birdie putt at the fifth before adding another at the par-five ninth to turn in level par.
Her back nine would mirror her front with a pair of bogeys – at the 11th and 14th – being blotted out by birdies at the 15th and 18th.
Walsh, showing fine form in 2025 on the Ladies European Tour, also turned in level-par after a bogey at two and a birdie at a very generous ninth hole that had coughed up a couple of eagles on Thursday. She briefly moved under par at the 11th before instantly giving that shot back, parring out from there.
Foster made a rollercoaster start to her round with two birdies and a double bogey inside the first four holes, before steadying the ship with a run of pars. Bogeys on 11 and 12 derailed her and were closely followed by a double bogey on 14 and another bogey on 17.
The Dublin native did pick up a shot on the closing par five 18th hole but currently finds herself four shots off the projected cutline.
Championship co-leader Okayama made an impressive start shooting a four-under-par opening nine, despite a bogey on the first, while Takeda carded seven bogeys and a double in Thursday's morning wave.
Pre-tournament favourite Lottie Woad shot an opening round of 72 to join the Irish women on level par. The in-form English star mixed four birdies with four bogeys on the Welsh links.
The most recent Open champions, Lydia Ko and Lillia Vu signed for rounds of 73 and 74 respectively while world number one Nelly Korda hopped off the par train with a birdie on 18 to join the congested chasing pack at two-under-par.
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