Welcome to Bag Spy, a GOLF series devoted to understanding the crucial equipment choices that define a player’s bag. With the help of players and/or their expert fitters, we dig deep beyond the photos to examine setups, specs and the thinking behind them. In this installment, GOLF Associate Equipment Editor Jack Hirsh takes you inside Si Woo Kim’s bag and new equipment setup for 2026.

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At first glance — and depending on what course you catch him — Si Woo Kim has a pretty old-school bag.

Driver, 3-wood, 5-wood, 3-iron through pitching wedge and just two wedges, a 52˚ and a 60˚. We don’t see a lot of that set-up on the PGA Tour anymore.

But a deeper dive and conversation with Callaway Senior PGA Tour Player Development Representative Kellen Watson shows Kim actually has a unique relationship with gear. He focuses strictly on looks, and if it passes the first couple of swings, there usually won’t be much hesitancy with putting it in the bag.

“If there’s something that fits his eye very nicely, you can be damn sure that either the wedge that it might be or the set of irons or the driver or whatever, it’s going in play like right away,” Watson told GOLF. “The performance stuff, we’ll incrementally get exactly where we need to get to. But aesthetically, if it’s pleasing to his eye, there’s nothing bigger. If it goes through the ground perfectly, it’s going in the bag.”

Watson called Kim a “corporate dream” because he’ll put almost any club in his bag as long as it meets his eye test.

That’s notable because Kim held onto his Paradym Ai-Smoke Triple Diamond driver for two years before moving into the Quantum Triple Diamond this season.

But he’s not afraid to try anything, and, in fact, Watson has to prevent him from trying too much.

“He gets some ideas, and he’ll just do it behind my back,” Watson said. “That’s why I try to stay in front of him all the time so we don’t allow him to do anything like that.”

Watson also has to rely on Kim’s caddie, Manny Villegas, to help maintain Kim’s clubs. It’s usually Villegas who asks for regrips or loft/lie checks.

“Manny’s almost playing offensive coordinator and Si Woo’s just the quarterback, just taking the play calls,” Watson said.

So far that’s been working well this season, as Kim, despite a bulky putter, had four top-11 finishes in his first four starts this season, including two top-5s. He’s 9th in the FedEx Cup standings and second in Strokes Gained: Approach with Callaway’s yet-to-be-released Apex MB ’26 irons.

Kim and Villegas, the brother of five-time Tour winner Camillo Villegas, form one of professional golf’s most unlikely player-caddie duos, but they’re also perhaps the most laidback and fun.

“I still think they should make a TV show of him and Manny, almost like there’s a sequel of ‘Rob & Big.’ I would watch that. I would watch them talk to each other all day long, every day,” Watson said. “I don’t think there’s anybody there you want to be around more than Si Woo when you’re playing golf. And that just kind of goes for every day anyway. Some of it’s just because you never know what he’s going to say next.”

Kim’s golf bag embodies much of that persona.

Keep reading below to dive into the bag of one of the PGA Tour’s best characters, Si Woo Kim.

Breaking down every club in Si Woo Kim’s bag

Ball

2022 Callaway Chrome Tour Dot

As a player who plays a fade and generally plays at a spin surplus throughout the bag, Kim is one of the many users of Callaway’s Chrome Tour Dot golf ball, a Tour-only version of the Chrome Tour X.

“Just the higher spin guys — it’s just the flight’s a little bit better for him. The spin control is a lot better for him,” Watson said of the ball, which is also played by Xander Schauffele.

The Dot has an identical aero package to the Chrome Tour X, but it reaches a slightly lower peak height due to reduced spin. Otherwise, it flies similarly.

Players who play a fade generally are going to spin the ball more than players who draw it, so being able to retain control and wind performance with a touch lower spin, while keeping launch, speed and feel the same, is a good match for Kim.

Callaway 2026 Chrome Tour X Golf Balls

SPEED TECHNOLOGY
Revolutionary new Tour Fast Mantle that increases distance through an optimized core/layer system.
ADVANCED SEAMLESS TOUR AERO®
Incredible distance and flight consistency on every shot.  
PRECISION TOUR URETHANE COVER  
Incredible feel and wedge control.    
PRECISION TECHNOLOGY 
Provides the ultimate in consistency. Every detail in the design, manufacture, and testing of the Chrome Tour X ball has been engineered to ensure maximized performance throughout your game.

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ALSO AVAILABLE AT: PGA Tour Superstore

Driver

Specs
Callaway Quantum Triple Diamond 9.0
Actual Loft: 8.9˚
OptiFit Setting: N/-1
Weights: 7 g front, 9 g back heel, 1 g back toe
Shaft: Fujikura Ventus Black VeloCore+ 6-X
Length: 44 15/16″ EOG
Tipping: 1″
Swingweight: D3.4

Stock Carry: 290 yards

When it comes to his driver, there isn’t much unique about Si Woo Kim’s, but it is notable given he did not switch to Callaway’s Elyte driver last season.

You would think, after Kim hung onto a Paradym Ai-Smoke Triple Diamond for two seasons, that it would have been a long and arduous testing process to get him into a new Quantum Triple Diamond for this season.

But it took Watson only three swings.

“We did kind of a preliminary fitting at Sea Island,” Watson said. “I think we gave him the 8.5. I remember every interaction with him and Manny because they’re some of my most fun times on Tour. But I think he hit it twice. Little low spin. Nine-degree first shot, and it was like, ‘Can we play this this week?’”

The start line was also important for getting Kim to switch from his Ai Smoke, which is why you’ll see above in his specs he keeps the back weight on the heel side of the club to encourage a left start line.

Unfortunately, at the RSM Classic last fall, where Callaway annually does testing with their staff players for the new driver, the Quantum was not yet on the USGA conforming list.

But Kim got his driver in mid-November and he was one of the first to put it in play the first week of December at the Australian Open when it hit the conforming list.

One thing that Watson struggled with, however, was getting him to test a backup driver.

“He hates to do like a backup head, and I forced him to do like a backup head today (Tuesday at Bay Hill),” Watson said. “He’s like, ‘Nothing’s wrong with this one. This one will not fail.’ I’m just making sure, dude.”

Kim moved into the updated Fujikura Ventus Black with VeloCore+ during testing with the Elyte driver as they found the slightly softer profile had a better feel for him. It also aided his timing for a fade.

“If anything, a little less catch-up in the shaft, just being just like a touch softer is probably better for him, where the club will stay behind him at impact and he can kind of hit that fade a little bit better,” Watson said.

Callaway Quantum Triple Diamond Custom Driver

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ALSO AVAILABLE AT: PGA Tour Superstore, Callaway

Mini Driver

Specs
Callaway Paradym Ai-Smoke Ti 340 Mini Driver 11.5
Actual Loft: 11.2˚
Lie: 57˚
OptiFit Setting: -1/N (Flat Cog)
Weights: 14 g front, 5 g back
Shaft: Fujikura Ventus Black VeloCore+ 7-X
Length: 43.125″
Tipping: 2″
Swingweight: D3.1

In some ways, the mini driver has become synonymous with Kim, as he is famous for his DODs from anywhere.

Fairway, rough, other, you name it, Si Woo Kim has probably tried to hit a driver off the deck from it.

That was the impetus for Kim in sticking with his Paradym Ai-Smoke mini driver, because it was much easier for him to hit off the fairway.

Watson intends to show Kim the new Quantum Mini Driver soon, but wanted to get more insight from the club from Min Woo Lee and Max Greyserman, both of whom already have it in the bag.

Kim loves the ability to swing the Mini Driver flatter and not down on it like a 3-wood.

Fairway Woods

Specs
Callaway Quantum Triple Diamond 3-wood*
Loft: 13.2˚
Lie: 57.3˚
Shaft: Fujikura OG Ventus Black 8-X
Length: 42.875″
Tipping: 1.5″
Swingweight:

Stock Carry: 258

*The Mini Driver is primary, but the 3-wood goes in on courses where he thinks he might need it

Specs
Callaway Quantum Triple Diamond 5-wood
Loft: 16.4˚
Lie: 58˚
Shaft: Fujikura OG Ventus Black 10-X
Length: 42 1/16″ EOG
Tipping: 2″
Swingweight: D4

Stock Carry: 237

While Kim doesn’t use the 3-wood often in favor of the longer Mini Driver, when he does, he likes to be aggressive with it. It’s to the point where Watson compared his divots to Sergio Garcia, one of the best and also steepest fairway wood players of all time.

The 5-wood is a better story as Kim previously played a Rogue ST LS 5-wood since the club came out in 2022.

That club was a “complete weapon,” Watson said, and was the club he used to make the longest hole-in-one in major championship history last year at Quail Hollow’s 252-yard par-3 6th.

But in the fall, Kim wanted to shorten the club and did so while in Japan for the Baycurrent Classic. Why?

“I don’t know. I have no idea!” Watson said. Remember when Watson said he had to get between Kim and some of his “ideas?” This is why.

The club never felt the same to Kim after that. Watson built him a new 5-wood before the start of the season and the 3-wood just so he has options and doesn’t have to look for a new club in the middle of the season.

Callaway Quantum Triple Diamond Custom Fairway Wood

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ALSO AVAILABLE AT: PGA Tour Superstore, Callaway

Irons

Specs
Callaway Apex MB ’26 3-PW
Shafts: KBS Tour V 125
Lofts: 19.3/21.4/24.9/28.5/32.3/36.6/40.5/44.5
Lies: 60/60.3/61.1/61.5/61.7/62.3/62.9/62.6
Length: 7-iron 37″ EOG
Swingweight: D3 (“Or whatever feels good sometimes” – Watson)

3-iron Stock Carry: 221
7-iron Stock Carry: 174

Kim is one of a growing number of players on Callaway’s unreleased Apex MB ’26 prototype irons. He has played blades at times throughout his career, but not since his first year with Callaway in 2018.

But when Kim first tested the new blades, like all of his other changes, the decision to switch was almost instant. Again, the swap was driven more by visuals.

Watson says the new MB has a longer blade length and a more Japanese-inspired pinched toe shape, similar to the X Forged, which was all familiar to him. Kim was one of just three staffers previously playing the Apex CB ’24, primarily due to the longer blade length.

“I think the longer the blade length for him, I think the better the results he gets,” Watson said. “For him, a longer blade length, the higher toe, the matched window of launch and spin being pretty much exactly where you need it — I think that is the determination of, is it going in play?”

In testing, Watson said the new MB “hits more of that CB kind of window” launch conditions which made the switch simple for Kim.

Looking at his specs, you’ll notice his irons are all bent 1-2 degrees strong. That’s not done for launch/spin or even turf interaction reasons. Keeping with the theme here, that’s all done to fit Kim’s eye. He’s played the stronger lofts since before he signed with Callaway in 2018.

“If there’s something that really fits his eye — he’s a lot about aesthetics — if there’s something that fits his eye very nicely, you can be damn sure that either the wedge that it might be or the set of irons or the driver or whatever, it’s going in play like right away,” Watson said.

Kim’s high-spin tendencies allow him to play the blades all the way through to the 3-iron, a rarity on the modern PGA Tour where even 4-irons are starting ot become extinct.

But the 3-iron doesn’t actually get used that often and, Watson said, sometimes he’ll even be content with rolling with just 13 clubs.

Callaway Apex MB Custom Irons

The new Apex MB Irons are developed for the absolute best in the game who are looking for a high level of performance in a modern Tour blade. With our Dynamic Sole Design, it provides more efficient turf interaction, enhanced workability, and the classic feel that elite players expect.
A PURE BLADE IN A MODERN DESIGN
The new Apex MB Irons are developed for the absolute best in the game who are looking for a high level of performance in a modern Tour blade. With our Dynamic Sole Design, it provides more efficient turf interaction, enhanced workability, and the classic feel that elite players expect.
PURE FORGED PERFORMANCE
The Apex MB body and face are forged as one-piece in a proprietary forging process from 1025 carbon steel, creating the purest feeling iron imaginable.
PROGRESSIVE CG DESIGN FOR ADDED CONTROL
A progressive CG throughout the set improves trajectory control. The long irons feature a lower CG that promotes towering shots that land soft into greens while the short irons utilize a higher CG for a lower trajectory with more spin for added control.
DYNAMIC SOLE DESIGN FOR ENHANCED TURF INTERACTION
These irons feature a dual chamfer on the leading edge to cut through the turf more efficiently. A trailing edge chamfer provides relief from the turf after contact for enhanced feel. This Dynamic Sole Design maintains speed through the turf and promotes consistent contact on all shots.

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ALSO AVAILABLE AT: PGA Tour Superstore, Callaway

Wedges

Specs
Callaway Opus SP RAW
Lofts/Grinds: 52/10S @ 51.5˚, 60/8C @ 59˚
Shafts: KBS Tour V 125
Lie: 60.8/63
Length: 35″ EOG/34.625″ EOG
Swingweight: D3 (“Or whatever feels good sometimes” – Watson)

52˚ Stock Carry: 114
60˚ Stock Carry: 89

Just two wedges?! Yes! just two wedges.

While the conventional wisdom for a player with strong lofted irons is to usually add more wedges, Kim plays just a couple and relies on feel to gauge the proper distance.

“I think that has more to do with the incredible set of hands that Si Woo just has,” Watson said. “I think he does more of it just with his hands. Totally feel.

“He’s more of an artist than people kind of would lead you to believe.”

Unlike most pros on the PGA Tour, Kim doesn’t use a clock system to hit distance wedge shots.

Like the rest of the bag, Kim had little issue switching into the new Opus SPs.

“I think he picked up both of them, just put them in the bag, like, ‘Okay, you take these two. I’ll play these two,” without even the waiting,” Watson said. “It’s like… ‘Yeah… Cool.’”

His stamp job, done by Callaway’s legendary Anthony Taranto is uniquely Si Woo. If you don’t get the reference, recall this clip of Jordan Spieth from the 2017 Presidents Cup.

Callaway Opus SP Custom Wedge

SPIN POCKET CONSTRUCTION
A re-engineered 2-piece construction head design strategically reshapes mass to optimize CG locations. The Spin Pocket redistributes weight higher, raising the CG, and promoting a lower, more penetrating launch. The result is more spin and enhanced control, especially when you need to flight shots or attack tight pins.
NEW SPIN GEN 2.0 FACE
The most advanced face in OPUS history. A new 17° groove angle with tighter pitch spacing delivers more groove edge contact for more consistent spin across a variety of lies. Combined with a deeper cross-hatch laser pattern across the face, Spin Gen 2.0 produces enhanced friction for more bite and stopping power on all types of approach shots.
SHAPE 6 – TOUR-VALIDATED PROFILE
Trusted by Tour players for its clean, confident look at address, Shape 6 offers precise leading edge shaping and refined sole geometry. Shape 6 is the 6th and final iteration in the Opus prototype shaping phase, validated by Tour players and major champions. OPUS SP introduces progressive shaping in gap wedges to seamlessly blend with modern iron sets—creating a more cohesive setup from top to bottom.
X GRIND – VERSATILITY WITH BOUNCE
Back by popular demand, the X Grind returns in OPUS SP. Designed for shotmakers who want added bounce for forgiveness, without giving up versatility, the X Grind is ideal for players who like to open the face around the greens or play in firmer turf conditions. It’s the perfect blend of playability and performance in a wide range of shots and conditions.

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ALSO AVAILABLE AT: PGA Tour Superstore, Callaway

Putter

Putter: Odyssey O-Works 3T
Loft: 2˚
Lie: 70˚
Length: 33.5″
Insert: Microhinge
Grip: SuperStroke Zenergy Claw 1.0

The flatstick has been a club holding Kim back this season as he ranks second in Strokes Gained: Tee-To-Green this season, but is losing nearly seven-tenths of a stroke on the greens. While this year is one of his worst, Kim has never gained strokes putting since joining the PGA Tour in 2016.

This Odyssey O-Works 3T is new this season and Kim loves the look of it, but this week, he’s testing out a new Odyssey prototype TRTL mallet putter.

It’s the same putter that Min Woo Lee is using and it obviously passed the eye test for Kim to consider using it this week. The specs match his current O-Works 3T.

Putter has been a revolving door the past two seasons for Kim after he stopped using an Odyssey 2-Ball 10 Broomstick.

Watson doesn’t know exactly why the run with the broom came to an end — nobody does, he said — but he has his guesses.

“He might have been getting sick of the look and just wanted to look at something different,” Watson said. “That would be my answer… and that wouldn’t be odd as an answer to the question about Si Woo with anything.”

Will the new TRTL be the next one to have staying power? We’ll see if it even makes it to the bag at the Arnold Palmer Invitational.

Grips: Golf Pride MCC Blackout 58R

The author welcomes your comments at Jack.Hirsh@golf.com.

Want to overhaul your bag in 2026? Find a club-fitting location near you at True Spec Golf.