Australia's resurgent superstar negotiated some wild and windy morning conditions to post a solid first-round two-under-par 70 to sit three shots behind the late afternoon first-round clubhouse leader.
Bidding to complete women's golf's grand slam with a fourth career major after winning last month's PGA Championship, Lee offset three bogeys with five birdies at Royal Porthcawl GC on Thursday.
After a disappointing six on the reachable par-five 13th, Lee rebounded with a brilliant sand-save birdie on the last hole to be sitting tied for seventh after the morning wave of starters.
Eri Okayami and Rio Takeda carded five-under 67s to take the clubhouse lead as the Japanese contingent shone in the early stages. Compatriot Miyu Yamashita was a shot behind.
Chisato Iwai, Shiho Kuwaki and Mao Saigo all posted 69s, one stroke ahead of Lee, Thai world No.2 Jeeno Thitikul, Americans Andrea Lee and Amy Yang and Swede Ingrid Lindblad.
"I don't think I'm going to complain with a two-under start," Lee said.
"Some of the holes are just beasts out there.
"Sometimes you've got to take what you get and just make a bogey and get out of there and reset, try and make better score on the next hole.
"It's a major championship. You''re going to make bogeys. Just try to keep your emotions in check and take it one shot at a time."Lee's in-form compatriot Grace Kim, one of nine Australians featuring at golf's final major of the year, was also well positioned four shots off the clubhouse lead when she signed for a one-under 71.
After backing up Lee's PGA Championship win in June to give Australia two consecutive major victories with a stunning finish at the Evian Championship, Kim held her nerve down the stretch on Thursday to stay in the mix.
Kim was one over par at the turn before collecting two birdies on the back nine to remain in the mix for back-to-back majors.
She admitted it had been an attritional battle against the elements, saying: "So just try to keep grinding it out the next three days as well hopefully. This whole week, literally I think the best word to describe it is a grind."
"That's kind of what you're going to get throughout these weeks, this week anyway with the conditions. The wind did pick up certain holes, the sun came out, and then it disappeared.
"The amount of wind was up-and-down throughout the day. Knowing that, really just trying to hit fairways and greens and just make a lot of pars."
Fellow 24-year-old Australian super talent Gabriela Ruffels joined Kim at one under with a birdie at the last.
She said: "I think I played super solid on the front nine as well. Started to get it together on the back nine and make a few more putts. I think I was three-under on the back nine. Really happy with that."
Ruffels also faced down the conditions. "Sure, it's a British Open, just like a US Open. It's a tough test of golf. You're aware of that when you get onto the first tee," she said.
"Some breaks are going to go your way, some are not. It's staying patient throughout 18 holes, and that's the tournament.
But out-of-form world No.11 Hannah Green is almost certain to miss the halfway cut after opening with a seven-over 79 shocker.
It was also a tough start for fellow Australians Karis Davidson (five over) and Kirsten Rudgeley (six over).
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