2024 Graco SlimFit3 LX Review – The Skinny All-in-One Car Seat

Graco SlimFit3 LX/True3Fit LX 3-in-1 Carseat Review

An ultra-slim carseat that claims to fit 3-across in most mid-sized vehicles seems too good to be true but we were cautiously optimistic! Would it live up to its promises? Graco was kind enough to send us three Slimfit3LX seats, so we put the triplets through the paces.

  • Rear-facing: 5-40 lbs. AND child’s head is 1” below height adjustment handle
  • Forward-facing: 22-65 lbs., 49” or less
  • Highback booster: 40-100 lbs., 43-57”, at least 4 years old
  • Adjustable base with 2 rear-facing recline positions, 2 forward-facing recline positions, 1 booster recline position
  • No-rethread harness with 10 position headrest
  • Easy-to-read ball level indicator on each side
  • Energy-absorbing EPS foam
  • Seatbelt lockoff for forward-facing use
  • On-board harness storage for booster mode
  • Steel reinforced frame
  • Two optional cup holders
  • Machine-washable Rapid Remove™ cover
  • 10 yr lifespan before expiration
  • Made in China
  • MSRP $279.99
  • Fashions (Kunningham, Katrina, & Stanford)


Fashion: Bates (Navy/Gray)

True3Fit Bates

Difference between the SlimFit3 LX and True3Fit LX? The only difference is the fashions. Otherwise, they are completely identical. True3Fit LX is a Walmart exclusive for now and Walmart wanted its own version with a unique name. Whatever. Big retailers do that sometimes.

Difference between the SlimFit3 LX and the original SlimFit 3-in-1 models? The SlimFit3 LX is 2″ narrower by our measurements and has removable cup holders, along with some other structural differences. Full details can be found here: A Comparison of Graco SlimFit3 LX & Original Graco SlimFit Models


Minimum Harness height: 7” with infant insert; 8” without insert
Maximum Harness height: 17.75″
Shoulder belt guide height: 19.5”
External widest point: 16.5”
Shell height with headrest: 30.25”
Shoulder width: 14”
Crotch strap depth: inner slot: 3” with insert; 3 ¼ ”, 5”, 6” without insert
Seat depth: 12”
Seat weight: 18.8 lbs. with insert, 18.3 lbs. without insert

3-Across Advice

I took a pic of the narrowest convertible carseats on the market for 3-across situations (see our article on 3-across situations). All these seats are roughly the same width, but how they mesh together in vehicles is what makes them good (or bad) for 3-across.

Left to rt: Radian, SlimFit3, Fllo, Scenera Next

What sets the SlimFit3 apart in this group is that it’s a 3-in-1 which works well in all modes. The Clek Foonf, Clek Fllo and Cosco Scenera Next are just convertible seats (rear-facing & forward-facing), they can’t be used as a booster. The Diono Radian 3RXT seats are technically 3-in-1 seats with the option to be used as a booster but they are notorious for being outgrown quickly and not fitting kids well in booster mode.

Three-Across Rules for the SlimFit3 LX/True3Fit LX – Straight from Graco:
  • Touching is OK, but overlap is not. Installing three carseats across a back seat would be nearly impossible in most vehicles unless they touched in some manner. Overlap means there’s probably some jockeying for position, which means interference with proper installation.
  • Remove the cup holders if they get in the way 

You may want a SlimFit3 for a 3-across situation or because you need a narrow-ish carseat in general, or simply because you like the looks and features of the seat. The manual addresses 3-across installations overtly and in ways you may not realize. In the section just before rear-facing installation, there are tips for how to install, position, and use the features of the carseat.

Also, more subtly, each installation section begins with instructions on how to install with the seat belt. Most people don’t read Graco instruction manuals as often as I do (I read more Graco manuals than I do books or magazine articles), but all other Graco manual installation sections begin with LATCH. It’s a subtle difference, but they’re telling you that seat belt installation is their preference.

Why install with a seat belt? The lower LATCH connectors for the SlimFit3 can only be used in positions with standard LATCH spacing, like outboard seating positions or middle seats with 11” lower anchor spacing (also found in vehicles with 3 full sets of LATCH). Installing with LATCH limits the positioning of the carseat. With seatbelt installation, the SlimFit3 can be shifted slightly to one side or the other as the belt is tightened. The ability to position the carseat a little more to the left or to the right can make a big difference when you are trying to fit seats side-by-side. 

The LATCH connectors are somewhat difficult to remove from their storage area. You must press on a plastic tab then pull the connector horizontally toward your finger, which is in the way holding the tab down. You can get the connector over the tab and it will then hold it down for you, but it still takes a big horizontal yank to get it free. It’s . . . awkward.

There are also 3 tabs that hold the LATCH strap in place while it’s in storage. This is all right about the same place as the rear-facing belt path, but the tabs do NOT hold the LATCH strap in place while the carseat is installed with LATCH. Here’s what I’m talking about. See the tabs holding the LATCH strap nicely in place? ↓

Now see where the LATCH strap lays when the SlimFit3 is installed? ↓

Of course this may depend on your vehicle as well, but you get the picture.

So how does the SlimFit3 install? Pretty easily, especially with those wide belt paths. Anytime you have a 3-across, it’s going to be a tough installation with some tugging and sweating. Graco has done a very nice job smoothing out the belt paths to reduce hand scrapes. I’ll offer some pro tips I picked up from installing the triplets below.

A tip about 3-across situations, in general: max out harness before switching to booster mode! Use this carseat’s 5-point harness until your child’s shoulders reach the maximum harness height or until they hit the max 65 lbs. weight limit for the harness. In general, when you have a highback booster next to another carseat, no one will be able to get a hand in between the seats to buckle the seat belt. You may wind up leaving the seat belt buckled over the booster while having your child perform daily acrobatic acts to get under the seat belt and into the seat. That’s a daily struggle that you want to avoid for as long as possible. Keeping your kids in the 5-point harness for as long as they technically still fit, makes getting everyone buckled much easier. 


Rear-Facing Installation

  • When rear-facing, either of the rear-facing reclines can be used to achieve an appropriate recline.
  • The bottom cover unsnaps for access to the RF belt path.
  • Seat belts in vehicles built after 1996 lock in some manner. Most lock by pulling out all the way slowly, then letting the belt retract. To reduce tipping of the SlimFit3 because of the wide belt path opening, pull the shoulder belt tight first and hold it tight with the hand closest to the latch plate, then lock the seat belt with your other hand and feed the shoulder belt into the retractor.
  • The tighter you pull the seat belt, the higher up the shoulder belt will sit under the child’s thigh because of the wide-mouth belt path. Most kids probably won’t feel this, but if you have a sensitive child, they’ll feel the difference in height between their legs. If this happens and you can, install the seat with LATCH instead. If not, see the above bullet point for help with lessening that shoulder belt pull.
  • Start with a rear-facing installation in the center first for a 3-across because the seats will puzzle better that way
  • The SlimFit3 is a relatively compact front-to-back carseat, but taller drivers in compact cars may still find their legs cramped depending on what they drive. Try putting the driver’s seat more upright or move the RF carseat to a different position if you can.

Forward-Facing Installation

  • When forward-facing, either of the forward-facing reclines can be used to achieve an appropriate recline.
  • When installing with the seat belt, use the lockoff in the forward-facing belt path.
  • The backrest cover lifts up for easy access to the belt path.

Changing the LATCH strap from the rear-facing belt path to the forward-facing belt path involves sliding it under a metal bar inside the carseat. Pull the LATCH connectors close together, then slide the strap up the metal bar; slide it behind the harness and through the forward-facing belt path. We have a video to show you how:

LATCH Weight Limits
Rear-facing LATCH weight limit: 40 lbs.
Forward-facing LATCH weight limit: 45 lbs.

Center LATCH installations with Non-Standard Spacing
Not allowed. Lower anchors must be spaced 11″ across.

Inflatable Seat Belts
Graco has determined that the SlimFit3 CAN be installed with inflatable seat belts found in some Ford Motor Company vehicles. Other types of inflatable seat belts are still incompatible for use with the SlimFit3. When installing the SlimFit3 with an inflatable seat belt, make sure the lockoff is closed and thread the seat belt over the top of it. Lock the retractor to make sure the seat belt stays tight.

Booster Installation

  • The harness is stored on-board in the storage compartment. Only the chest clip and buckle tongs are stored inside the compartments. The buckle lays back into a spot under the child’s bum. Tech tip: recline the carseat first and the harness will stay put more easily in the compartment and you won’t need to be an octopus and wrangle it vertically.
  • When used as a highback booster, the seat can be secured with LATCH up to 100 lbs., the maximum weight limit as a highback booster. If the LATCH strap or connectors interfere with the vehicle buckle or seat belt in any way, store it in its storage location under the child’s thighs.
  • The recline position must be set to position 4, which is most upright.

I installed the SlimFit3 triplets in several vehicles with help from a couple of CPST friends in their vehicles. See below for our results. Of course, YMMV depending on your specific vehicle and trim line.

Passenger | Center | Driver Side

ICS = Graco SnugRide SnugLock 35

HBB = Graco TurboBooster Highback

2020 Ford Explorer 2nd Row

Graco submitted this to CarseatBlog for the review

RF | RF | RF

FF | FF | FF

FF | FF | RF





2019 Honda Odyssey 3rd Row

Graco submitted this to CarseatBlog for the review

FF | FF | FF

RF | FF | FF



2018 Tesla Model 3

Overall, the carseat installed typically for a Graco in the Model 3. A rear-facing center installation will be very difficult. What works:

FF | FF | RF as will the RF carseat behind the passenger.

FF | RF | FF

Skinny backless booster* | RF | FF

Skinny backless booster | FF | FF

*I suggest putting a belt-positioning booster rider on the passenger side because the buckle on the driver side is so far behind the center carseat that it makes it very difficult to find and buckle the seat belt.

2015 Nissan Versa

In this cramped back seat, the best configuration was with the RF seat in the center. The door didn’t want to close with 3 FF seats. Due to the wide angle of the lens, it looks like there’s overlap in the pics, but there’s not.

FF | RF | FF

Skinny backless booster | RF | FF

2014 Honda Odyssey 2nd Row

What doesn’t fit in an Ody? The triplets fit beautifully in any configuration with room to spare!

Highback booster (HBB) | RF | FF

FF | RF | FF

RF | RF | RF

FF | FF | FF


2011 Acura MDX

There was plenty of room for a 3-across in the MDX. I tried the center RF with the ceiling seat belt, but wasn’t happy with the inches of movement at the belt path, so I switched to a LATCH install. The MDX has 3 full sets of lower LATCH anchors. It definitely set the carseat closer to the driver’s side but not so much as to affect installation of the FF carseat and the RF install was so much better.

Highback booster (HBB) | RF | FF

FF | RF | FF

FF | FF | FF



RF | RF | RF


The SlimFit3 has a head support, body support pad, and harness covers.

Head support: Use rear-facing only; use is optional

Body support pad: Use rear-facing only; must be used if shoulders are below the lowest harness setting; once shoulders are above the lowest harness setting, use is optional

Harness covers: Must be used when forward-facing if child is between 22-25 lbs.; otherwise, use is optional; make sure they don’t interfere with chest clip placement at armpit level

The headrest and backrest pad ships in the lowest position with the backrest pad between the harness and touching the buckle so the child sits on it. This is how it should be used. Its design allows it to be folded under behind the child’s back, but Graco does NOT allow this use. 

There are 3 buckle positions from which to choose so your child isn’t sitting on the buckle, and any of them can be used rear-facing. Forward-facing, use the outer two buckle slots only.

There are no surprises as far as fit to child goes with this carseat. It’s a Graco carseat and they haven’t veered off their well-known track of carseats that fit children well from newborn to average 9-year-old. The SlimFit3 fit my larger newborn/1 mo old-sized doll well (0-3 mo. clothes are a little large on him): I even had to adjust the headrest up one notch for proper fit on him.


The cover can be thrown in the washing machine on gentle cycle. Hang to dry. The Rapid Remove cover comes in 5 or 6 pieces, depending on how you remove the cover. Removing and replacing the covers is fairly easy. I really like the Rapid Remove cover because you can select the section that needs to be cleaned instead of washing the whole thing. One super bonus: no elastics! However, I was practically begging for the elastics after trying to snap the cover back together—the snaps can be tough for someone with hand issues.

The cup holders are optional, SUPER easy to connect and disconnect, and dishwasher-safe. Listen for a solid “click” to know they’re attached properly.


The SlimFit3 is FAA-approved when used with the harness. If you’re using it as a booster seat, you can’t use it on the plane because booster seats require lap/shoulder belts. I think the SlimFit3 has awesome potential as a travel seat because it’s not a tremendously heavy seat (it’s downright lightweight as a 3-in-1!), it’s narrow, and it has the lockoff. I know that every ounce counts when your plane is at that last gate in the airport (they always are!), but it’s also nice to know that with the easy-to-use lockoff, you won’t need to figure out an unfamiliar vehicle’s seat belt locking mechanism at your destination when you’re tired and possibly frustrated.

This carseat has a lifespan of 10 years from the date of manufacture. It must be replaced after any crash, including a minor one.

  • Adjustable base with 2 rear-facing recline positions, 2 forward-facing recline positions, 1 booster recline position
  • Wide, smooth belt paths fit larger hands and keep them scrape-free
  • No re-thread harness with 10 position headrest
  • Easy-to-read ball level indicator on each side of carseat
  • Energy-absorbing EPS foam
  • Seat belt lockoff for forward-facing use
  • On-board harness storage for booster mode
  • Steel reinforced frame
  • Two optional cup holders
  • Nice LATCH storage
  • Machine-washable Rapid Remove™ cover
  • 10 yr lifespan before seat expires
  • No rear-facing lockoff
  • Removing LATCH connectors from storage is awkward
  • Snaps on Rapid Remove™ cover are challenging

I’ve really enjoyed getting to know the Graco SlimFit3 LX. Each carseat has its own personality and quirks and the SlimFit3 is no exception. The wide-open belt paths mean no more scrapes on hands when running a belt through the belt path. It’s a tall seat, typical for a Graco 3-in-1 product, so kids will make it to the full 40 lbs. rear-facing. But most of all, it’s skinny at the right price. The bang for the buck is there: RF, FF, highback booster in a carseat that’s 16.5” wide for $279. That’s hard to beat!

Thank you to Graco for providing the Graco SlimFit3 LX used for this review and for the vehicle test fit info (it’s hard work!). No other compensation was provided. All opinions expressed are those of the author.


CarseatBlog Experts Rating

Recommended: SlimFit3 LX and True3Fit LX


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