The Korean, the first and second round leader, signed for a one-over-par 71 to lead by a stroke from Thailand’s Panuphol Pittayarat and Phachara Khongwatmai, who carded 68 and 69 respectively.
“It was a tough day. I was a little out of sync, I’m not sure why,” said Kim, who is on 11 under.
“I am going to head straight to the range to work it out. I was certainly mentally tired. I was playing with two great Thai players, so it was tough. I am pleased the round is over and I can reset for tomorrow.”
He appeared to be in control after nine holes, after touring the front side in one under but the wheels came off on the homeward stretch with bogeys on 10 and 15.
The 31 year old is a six-time winner on the Korean PGA Tour but is looking for his first title on the Asian Tour, having made it through Qualifying School in 2020.
Recent form suggests he will not be far away today: he was joint fourth last week at the Blue Canyon Phuket Championship and claimed the LG Signature Players Championship last month on the Korean PGA Tour.
Kim narrowly held the lead all day until Panuphol, playing in the group ahead, drew level with him for the first time when he holed a 15-foot birdie putt on 17.
But the Thai golfer dropped a shot on the par-four 18th after hitting his approach short, chipping to three feet and missing the putt.
Said Panuphol: “I am still struggling with a shoulder injury, but I am playing well, enjoying the course and it’s great to be in contention. It’s going to be tight tomorrow with so many in contention.”
Panuphol, affectionately known as Coconut, last won on Tour at the 2018 Thailand Open, a year after winning the Indonesian Open.
‘Win number three would be amazing but there’s a lot of work to be done before that,” he added.
Phachara, still only 22-years-old, is another looking for his first Asian Tour victory after a plethora of top finishes ‒ he has finished second on six occasions.
“We had a battle on the back nine and I am sure it will be the same tomorrow,” said Phachara, who was paired with Kim.
The trio will play in the final group today making for a thrilling finish to the event.
Thailand’s Chanachok Dejpiratanamongkol, Prom Meesawat, Natipong Srithong, and Korean Yikeun Chang finished tied for fourth on eight under.
The tournament is the second and final leg of the Asian Tour Phuket Series, which has marked the resumption of the Tour after a 20-month COVID-19 enforced break.
Scores after round 3 of the Laguna Phuket Championship being played at the par 70, 6770 Yards Laguna GP course (am - denotes amateur):
199 - Bio Kim (KOR) 62-66-71.
200 - Panuphol Pittayarat (THA) 68-64-68, Phachara Khongwatmai (THA) 66-65-69.
202 - Yikeun Chang (KOR) 69-65-68, Prom Meesawat (THA) 68-65-69, Natipong Srithong (THA) 68-64-70, Chanachok Dejpiratanamongkol (THA) 63-67-72.
203 - Dodge Kemmer (USA) 70-69-64, Denwit Boriboonsub (THA) 69-68-66, Ryan Lumsden (SCO) 68-67-68, Steve Lewton (ENG) 66-68-69, Kosuke Hamamoto (THA) 66-67-70.
204 - Joohyung Kim (KOR) 66-69-69, Scott Hend (AUS) 71-63-70.
205 - Donlaphatchai Niyomchon (THA) 69-69-67, Hongtaek Kim (KOR) 68-70-67, Mathiam Keyser (RSA) 69-69-67, Chang Wei-lun (TPE) 69-68-68, Sadom Kaewkanjana (THA) 68-65-72.
206 - Zach Bauchou (USA) 67-70-69, Berry Henson (USA) 68-72-66, Yoseop Seo (KOR) 66-67-73, Veer Ahlawat (IND) 66-67-73.
207 - Kasidit Lepkurte (THA) 66-72-69, Paul Peterson (USA) 69-69-69, Wade Ormsby (AUS) 70-69-68, Sihwan Kim (USA) 71-67-69, Trevor Simsby (USA) 68-70-69, Bongsub Kim (KOR) 67-72-68, Witchayapat Sinsrang (THA) 71-66-70, Shiv Kapur (IND) 67-74-66, Suteepat Prateeptienchai (THA) 70-65-72, Pavit Tangkamolprasert (THA) 69-72-66.
208 - Jarin Todd (USA) 68-70-70, Waris Manthorn (THA) 67-71-70, David Langley (ENG) 71-68-69, Travis Smyth (AUS) 63-74-71, Ben Eccles (AUS) 71-66-71, Vanchai Luangnitikul (THA) 66-70-72, Miguel Tabuena (PHI) 69-67-72, Sattaya Supupramai (THA) 71-70-67.
209 - Danthai Boonma (THA) 71-67-71, Micah Lauren Shin (USA) 72-67-70, Ratchanon Chantananuwat (am, THA) 68-72-69, Ben Campbell (NZL) 70-70-69, S Chikkarangappa (IND) 68-69-72, Suttijet Kooratanapisan (THA) 69-67-73.
210 - Khalin Joshi (IND) 67-71-72, Poosit Supupramai (THA) 67-70-73, Charng-Tai Sudsom (THA) 68-72-70, Piya Sawangarunporn (THA) 70-66-74, Rashid Khan (IND) 69-65-76.
211 - Nirun Sae-Ueng (THA) 69-72-70, Ian Snyman (RSA) 70-71-70.
212 - Settee Prakongvech (THA) 69-70-73, Siddikur Rahman (BAN) 68-71-73, Nicholas Fung (MAS) 69-69-74, Nitithorn Thippong (THA) 70-69-73, Atiruj Winaicharoenchai (THA) 68-72-72, Sarun Sirithon (THA) 66-74-72, Rory Hie (INA) 70-71-71, Sungho Lee (KOR) 69-72-71, Justin Quiban (PHI) 69-72-71, Udayan Mane (IND) 66-75-71.
213 - Taehoon Ok (KOR) 68-70-75, Bjorn Hellgren (SWE) 71-68-74, Poom Saksansin (THA) 73-67-73.
214 - Andrew Martin (AUS) 69-71-74.
215 - Gavin Green (MAS) 73-66-76.
216 - Chapchai Nirat (THA) 67-72-77, Galven Green (MAS) 69-72-75, Pawin Ingkhapradit (THA) 69-72-75.
219 - Karandeep Kochhar (IND) 68-72-79, Cory Crawford (AUS) 70-71-78.
220 - Itthipat Buranatanyarat (THA) 71-70-79.