Snedeker's 65 came on the easier North Course, while Choi played the longer, more difficult South Course. Players will rotate courses in round two, before the South Course hosts the final two rounds.
Former Masters champion Mike Weir headlines a group of eight players tied for third at minus-6. Of the top 10 on the leaderboard, only Choi and Josh Teater (66) played the South Course.
Tiger Woods, who has won this title six times, bogeyed two of his last four holes as he carded a 4-under 68 on the South Course. He is tied for 20th.
Phil Mickelson, a three-time winner, mixed four birdies and four bogeys in a round of 72 that left him tied for 90th.
Woods opened with a birdie on the first. He faltered to a 3-putt double-bogey at No. 4. He got one stroke back with a birdie on the fifth, then he holed a bunker shot for eagle at six.
The six-time winner made the turn at minus-4 after back-to-back birdies at eight and nine.
Woods again made consecutive birdies at 12 and 13 to move within one of the lead. He stumbled to a bogey at the 15th, and failed to get up and down for par on No. 17 to slide three back. Woods ended there when he could only par the par-5 18th
"There were perfect conditions to do it. The wind wasn't blowing and the fairways were fast enough still that we could get the ball down there. With a little bit of rain, the greens were pretty receptive," Woods said in a televised interview of the scoring conditions. "Of all the days, this was the day to do it on."
Snedeker played the back nine on the North Course first and started with four pars in a row. He dropped in his first birdie on the par-5 14th.
The reigning FedExCup champion poured in four consecutive birdies from the 16th to jump to minus-5.
Snedeker parred five straight from the second. He converted a birdie effort on the seventh and made another birdie at eight. Snedeker parred the par-5 ninth to share the first-round lead.
"These greens bring out my best. I put in a lot hard work yesterday on the putting green because I wasn't real happy with the way I was rolling it. I came out here today and rolled it the way I wanted to and hit my lines," Snedeker said of his putting.
Choi also played the back nine first, but he was on the South Course. After three pars in a row, Choi drained four straight birdies from the 13th.
At the 17th, Choi stumbled to a bogey, but he atoned for that mistake with a birdie on the par-5 18th.
On the front side, Choi parred the first five holes before catching fire down the stretch. He converted back-to-back birdie tries at six and seven. Choi rolled in an 8-footer for birdie at his final hole to gain a share of the lead.
Weir was joined in third place by two-time runner-up Charles Howell III, Luke List, Teater, Ross Fisher, Billy Horschel, Scott Stallings and Adam Hadwin.
Jerry Kelly and Bo Van Pelt are among nine players tied for 11th at 5-under 67. Among the large group tied at minus-4 with Woods are Ryo Ishikawa and Vijay Singh.
NOTES: Kyle Stanley, who triple-bogeyed the 72nd hole last year, then lost in a playoff, struggled to a 3-over 75 ... Reigning Masters champion Bubba Watson withdrew due to illness before his round, and was replaced by Billy Mayfair, who stumbled to a 2-over 74.