The former Solheim Cup player opened with back-to-back birdies and made more at the fifth, 10th and 17th.
Morley finished two shots back from the early pace-setter Aki Takamura, of Japan, who had five birdies in a row from the fifth and was five under after 13 holes. "It's a good start but it should have been even better as I three-putted twice," said Morley, who is from Sale, Cheshire.
Four players shared the clubhouse lead on four under - Hiromi Kobayashi and Toshimi Kimura, of Japan, American Laura Philo and Australia's Corinne Dibnah, who overcame the pain barrier to shoot her 69.
Another four Britons - Lisa Hackney, Helen Dobson, Pam Wright and Julie Forbes - all finished with two-under 71s, while Laura Davies recovered from a shaky start to stay in touch on a day of calm, ideal scoring conditions.
The 1986 champion dropped two shots in the first three holes but bounced back with a birdie at the fourth and an eagle three at the long sixth to reach the turn in one-under-par 34.
Australia's Karrie Webb, the pre-event favourite, dropped shots at the last two holes for a 71, but her compatriot Dibnah had a remarkable round to share the clubhouse lead. In agony and suffering from severe back spasms, the 1988 champion had to call a doctor on the 13th fairway.
Dibnah has a long history of back trouble and it was on the practice ground on Tuesday that she felt the first twinge. "But it wasn't too bad until this morning," she said. "When I woke up it was a nightmare and I really just went out hoping to punt it up the fairway and not disgrace myself."
But, rather than embarrassing, her effort was simply heroic. She made four birdies and just one bogey despite the suffering that forced her to call the doctor. "She gave me a muscle relaxant but it was a case of trying to swing through the spasms and it certainly eased off over the last four holes," she added, before being taken off in a golf cart for some much-needed physiotherapy.Reuse content