Graco Tranzitions SnugLock 3-in-1 Harness Booster Review

2021 Graco Tranzitions SnugLock Forward-Facing Harness Booster

Tranzitions SL in Fairmont“Hooray!”

It’s not something you hear a lot so early in the year 2021, but this new seat is something parents will want to celebrate! The popular Graco Tranzitions, a narrow, budget-friendly forward-facing combination carseat now has an upgraded version with several added features including SnugLock, Graco’s tensioning lockoff. Introducing the Graco Tranzitions SnugLock Harness Booster!

SnugLock is a locking mechanism built inside the belt path for installing the car seat with either a seat belt or the LATCH strap. It simplifies the installation process and helps you achieve a proper installation. When installed properly, the car seat should not move more than 1 inch when you test for tightness at the belt path. Whether you install with LATCH or a seat belt, don’t forget to tether your seat using the newly marked tether strap.

Another new feature is the “Hassle Free Harness”, which keeps the harness out of the way when you are loading and unloading your child. A great feature when you are wrangling squirmy kids! These are all things that parents of preschoolers can cheer about—even if they aren’t able to actually DRIVE their kids to school this year.

Four years ago I reviewed the original Graco Tranzitions Harness Booster. Our family has loved this car seat because it’s budget-friendly, narrow and lightweight, and has generous weight and height limits. And guess what? This new and improved version is still an excellent value, still narrow and lightweight, and will last us several years. Let’s take a look at this new Tranzitions SnugLock model!

Tranzitions SnugLock Weight and Height Limits
  • Forward-facing with 5-pt harness: 22–65 lbs., 27–49 inches, at least 1 year old*
  • Highback Booster: 40–100 lbs., at least 4 years old*, 43–57” tall
  • Backless Booster: 40–100 lbs., at least 4 years old*, 43–57” tall

*Check your state laws and the AAP/NHTSA recommendations. The AAP recommends all infants and toddlers should ride in a rear-facing seat until they reach the highest weight or height allowed by their car safety seat manufacturer. Children should use the built-in harness system for as long as possible until they reach the maximum forward-facing weight and height for their car seat.

It’s worth pointing out that this is a forward-facing only carseat that can also be used as a highback booster and eventually as a backless booster. Graco refers to it as a “3-in-1” product which can be confusing because many parents think a 3-in-1 carseat always means Rear-Facing/Forward-Facing/Booster. However, in this case, it means Forward-Facing/Highback Booster/Backless Booster. This is a Stage 3 carseat that is most appropriate for pre-school and school-aged children.

Tranzitions SnugLock SnugLock Overview
  • No-rethread harness with 9 height positions
  • SnugLock tensioning lockoff
  • Converts from forward-facing 5-pt harness to highback booster to backless booster
  • Fuss Free Harness pockets
  • Dual cup holders
  • Removable and machine washable cover
  • Optional body cushion and harness covers
  • Can use LATCH in booster mode
  • FAA approved for use in aircraft (in harnessed mode only)
  • Lifespan is 7 years from date of manufacture
  • Made in China
  • MSRP $149

Tranzitions SnugLock Fairmont Graco Tranzitions SnugLock Sutherland

Tranzitions SnugLock Measurements
  • 9 Harness slot heights: from 12” up to 18”
  • Shoulder belt guide height: 19.5″ to belt guide opening
  • Crotch strap depth: 6” &  7.5”
  • Seat depth: 13” with back, 15” without back
  • Interior seat width (at narrowest point): 11″
  • External widest points:
    • Width across armrests: 18″
    • Width across front with optional cup holders: 19″
    • Width across front without optional cup holders: 17.5”
    • Width at bottom of base: 17”
  • Shell height: 26.5” – 33”
  • Seat weight: 15.1 lbs.
Installation/Fit to Vehicle

SnugLock Built-In Lockoff

I have yet to find a vehicle or seating position wherein the Tranzitions SnugLock Harness Booster does not install well. The LATCH and tether installation was initially pretty secure, but was made even tighter when the SnugLock compartment was closed, eliminating any remaining slack. The seat belt and tether installation was a breeze! Since both methods provided a solid installation I could choose which method I preferred and I found the seat belt and tether so much easier thanks to the awesome SnugLock lockoff.

The original Tranzitions model without the lockoff only installs easily with a seatbelt in some vehicles. It seems to be hit or miss, with some vehicles being incompatible while other vehicles are fine. In my experiences with the original Tranzitions model, there were times when I had to utilize all my CPST techniques to eke out enough slack from the seat belt to appropriately secure the seat to the vehicle.

With the SnugLock feature eliminating the need to lock the seatbelt at the retractor, there is less belt webbing to tighten. Also, the way that the seatbelt is pressed down into the channel of the SnugLock lockoff, any extra tension I cannot remove myself is done so mechanically when shutting the SnugLock door.

Narrow Footprint 

One of the biggest selling points for me about the Tranzitions is how narrow it is; allowing for multiple seats across a row in some vehicles. This seat rivals many high-end brand carseats known for their narrow footprint, but at a much more budget-friendly price. In the back row of my old van I could easily install two Tranzitions in the outboard positions, with room between them for a smaller child. With only about 13 inches available in the center seating position, my seating options were limited to either a child who is tall enough to ride without a car seat or a narrow booster. A BubbleBum booster fit here perfectly. While the shell of the Tranzitions is narrow (17 inches at the narrowest point of the base) the interior seat width (at the most narrow point) is a comfortable 11 inches. It is plenty wide to accommodate my four year old in harness mode as well as my older child who could use this as a booster.

Installation with seat belt

  • SnugLock lockoff eliminates need to utilize other seatbelt locking methods
  • Easy access to SnugLock and belt path from the front of the seat. (lift padding)
  • Vehicle headrest may need to be raised or removed to eliminate gap between car seat and vehicle seat
  • Can be installed in harness mode using either a lap-only or lap/shoulder seat belt
  • Always use the top tether when installing in harness mode (if a tether anchor is available)

Installation with LATCH (lower anchor strap)

  • LATCH can be used to install the carseat in harness mode for a child weighing up to 45 pounds. If using the harness for a child weighing more than 45 pounds, you must install using the vehicle seat belt and tether.
  • Vehicle headrest may need to be raised or removed to eliminate gap between car seat and vehicle seat
  • Always use the tether when installing seat with LATCH
  • If you are not using the lower anchor and tether straps, be sure and secure them to the storage rings on the seat

Using LATCH in Highback Booster Mode:

  • Highback booster can be secured using LATCH, if vehicle manufacture allows.
  • Be sure to use either the latch strap strap or seat belt to secure booster when not in use as an unsecured booster can be hazardous to other passengers in a crash or sudden stop.

LATCH Weight Limit:

Harness mode: 45 lbs.

Booster mode: No weight limit. Can secure the Tranzitions SnugLock using the lower anchor latch strap and top tether while the child uses a seat belt for restraint – as long as vehicle manufacturer allows and the LATCH connectors do not interfere with any vehicle seat belts or buckles.

Center LATCH installations with Non-Standard Spacing:

Graco allows center LATCH installation where lower anchors are spaced more than 11” apart.  Check your vehicle owner’s manual for LATCH positions.

Inflatable Seat Belts

Graco has determined that the Tranzitions SnugLock 3-in-1 Harness Booster SnugLock 3-in-1 Harness Booster cannot be installed with inflatable seat belts found in some Ford, Lincoln, and Mercedes vehicles, and in some airplane seats.

Fit to Child

In harness mode: 

The Tranzitions SnugLock Harness Booster can be used in harness mode with children weighing 22-65 lbs. and 27-49 inches. It is best that your child remain rear-facing as long as the weight and height recommendations of their rear-facing car seat allows. This is a great fitting seat for a child transitioning to a forward-facing seat and will continue to secure your child as they grow!

The harness is incredibly convenient as you do not have to uninstall the car seat to thread the harness straps higher as your child grows. Simply squeeze the gray adjustment lever at the headrest and you can raise or lower the headrest, side wings, and harness strap heights. When forward facing the straps should always be AT or SLIGHTLY ABOVE your child’s shoulders.

While the maximum height for the seat in harness mode is 49 inches, every child is different, and some children with shorter legs and longer torsos may discover that their shoulders surpass the highest harness position before the 49 inch limit. Please note that once your child’s shoulders are above the highest harness slot, they have outgrown the harness and need to use the seat in booster mode.

In high-back booster mode: 

A change that I appreciate Graco making in the four years since my review of the Tranzitions car seat, is that they raised the lower weight limit for the booster to 40 lbs., the lowest height requirement up to 43 inches, and the minimum age to 4 years old (up from 30 lbs, 38 inches and 3 years old). This industry trend of slowing down the race to outgrow car seats is a reminder that as highway speeds increase and drivers become increasingly more distracted, we need to utilize the innovations available to protect our smallest passengers.

In my experience with the Graco Tranzitions car seats, my daughter was able to use the 5 point harness until her shoulders surpassed the highest harness slot when she was 48 inches, 58 pounds, and 7 years old. Many children could remain in a harness car seat much longer than they do because the children and their parents are excited to move on to the next seat and don’t take advantage of inexpensive car seats with higher weight and height limits like the Graco Tranzitions. Four years old, 40 lbs, and 43 inches are the absolute minimum for a child to be using the booster mode. A child is safest using the 5 point harness of the forward facing seat as long as possible.

Once the child has outgrown the five point harness of the forward facing seat it is easily transformed into a high-back booster. From the back of the seat, unloop the harness straps from the metal yoke on the harness adjuster strap, then unthread the harness straps from the back of the seat through the slots to the front of the seat. From the two slots near the child’s hip, pull the metal H clips up through the hips to the front of the seat. The crotch strap is also easily removed by pulling the metal H clip up from under the seat through to the top of the seat. There is no on-seat storage for these items so find a safe place to store them for future use.

The Tranzitions features an open loop shoulder belt guide that is bright red and impossible to miss. It is a bit tricky for my kids but it is not at all hard for an adult to do. Since the guide holds the seat belt in place between uses, I can thread it for my kids one time and it is ready for them to strap themselves in every time.

In backless booster mode:

Graco lists the weight and height minimums and limits for the backless booster as 40-100 lbs. and 43-57 inches. Again, just because your child has reached the minimums does not mean they should move into a booster. A child is safest riding in a five point harness as long the seat allows. This seat is easy to turn into a backless booster when your child is ready. Simply fold the back of the booster toward the ground and lift the back up out of the seat gutter to transform the high-back booster into backless booster mode.

Taking the back off the Tranzitions booster seat makes the seat two inches deeper giving a long legged child extra thigh support. The seat comes with a removable shoulder belt positioning clip to adjust the vehicle seat belt comfortably across the child’s chest and shoulder.

Optional Accessories 

The Graco Tranzitions SnugLock 3-in-1 Harness Booster has not one but TWO cup holders! That is a really big deal when you are trying to focus on driving and not passing a drink or snacks back to your child. If a narrow seat is more important to you than cupholders, you can easily remove the cup holders for an extra couple inches.

This car seat also comes with two shoulder harness covers and a lightly padded body cushion. There are no height or weight limits specified for use of these items in the manual so they can be used at the discretion of the child and caregiver.

The instruction manual does specify, “DO NOT use accessories or parts other than those provided by Graco. Their use could alter the performance of the car seat.”

Carseat options, maintenance and shell 

Fabric Options

In the comparison photos of the original versus the upgraded Tranzitions seat, you can see our car seat from 2016 has seen a lot of long road trips and the accompanying snacks. But for how infrequently I take off the cover and give it a thorough wash, the black “Proof” option has actually worn pretty well. The newer Tranzitions car seat that we received is with the grey, “Fairmont,” color option and while a very attractive light grey and black combo, since taking the pictures, the light grey fabric is very revealing of any spills or other stains. Neither of my kids who tried the seat mentioned that they were cooler in the “Fairmont” fashion carseat as it had a bit of mesh paneling on the back, but it’s possible that bit of air movement helps keep the heat down. There is one other color option for the Tranzitions SnugLock 3-in-1 Harness Booster which is the black or “Sutherland,” fashion, which I would guess would be better at camouflaging a well-used seat.

Fabric Maintenance

With the “Fairmont” fabric option the cover is made of two different materials. The black material feels identical to that of the older Tranzitions seat in the “Proof” fabric option. It’s texture is much like a wet suit and while this smooth fabric is easy to wipe clean, over the years it has become snagged from the Velcro of shoes in the lower seat area.  In that same lower-seat area of the new Tranzitions SnugLock seat, the material of the “Fairmont” option is grey, and feels a bit more rough. While this fabric seems more durable, like it could stand up to Velcro better, it does, like I mentioned earlier, show stains more easily.

If you need to do a more thorough cleaning than just wiping with a wet cloth or sponge the covers are all machine washable! Taking the fabric off to throw in the washer (and later remembering how to put it all back on) is not at all difficult.There are only two snaps securing the main seat cover to the upper shell and two hooks securing the seat cover to the seat shell.  You can wash the fabric covers in the washing machine with cold water on delicate cycle and drip-dry.  Do not dry in the dryer or use bleach. The manual does a good job explaining further maintenance in section 8.

Carseat Shell Construction 

Without the cover on the Tranzitions on you’ll notice Graco did not use any EPS/EPP foam in the construction of this carseat. Instead they used a manufacturing process called “blow molding” to create the energy absorbing hollow plastic side wings of the Tranzitions carseat.

Instruction Manual/Assembling the Seat

Comparing the 2016 Graco Tranzitions career with the 2020 SnugLock version I noticed a few changes. The newer instruction manual rarely uses the term, LATCH, when referring to the lower anchor system, which is why I have tried to adopt that verbiage in this review. As mentioned before, the weight, height, and age requirements were increased since the last manual. Graco also changed the manual to include parts of the 2018 American Academy of Pediatrics (AAP) revised guidelines on car seat safety.

The additional steps explaining how to install using the SnugLock feature are clear and have helpful images. It adds an additional 8 to 9 steps per installation method (vehicle belt and lower anchors respectively) and I think parents will find the instructions easy to follow.

In the 2016 review I discussed how the instructions manual left me wanting for certain information I needed to know. Such as: How to Assemble the Carseat!

If you are having a hard time figuring it out when opening your box, let me share with you what I discovered:

On page 47 of the instruction manual, in section 4-B Install Backed Booster Graco explains how to attach the back support to the seat, “Place Seat Back Hooks Into Gutters and Raise Seat Back.”  It is literally two steps; lay the back support with the hooks in the slots of the bottom seat then lift the back support up to create a 90 degree angle.  You will feel two small clicks confirming that the back is in the proper upright position.

With the Tranzitions car seat installed and supported by the vehicle seat there is no risk of the two parts coming apart.  However, if you try sitting in the unsupported seat, like carrying the carseat through the airport (it really is a great lightweight travel seat), find a way to secure the seat as it can easily come apart. I would recommend buying a car seat bag or using a luggage cart.

Overall I think the manual is thorough and especially appreciate that Graco sewed a pocket into the seat fabric for on-seat storage of the instruction manual.

FAA-Approval/Lifespan/Crash Guidelines

FAA Approval

When used in harness mode the Tranzitions can be installed in an airplane.  It CANNOT be used as a booster on an airplane as a lap and shoulder belt are required for use.

Lifespan and Crash Guidelines

Expires after 7 years from date of manufacture. Graco requires replacement after any crash.

  • SnugLock built-in lockoff
  • Inexpensive (MSRP $149.99)
  • Very Narrow (18 inches at widest point with cupholders removed)
  • Hassle Free Harness pockets for harness tongues
  • Lower anchor and tether connectors marked with same symbol as vehicle LATCH symbols
  • No-rethread harness
  • 3-in-1 carseat: 5 point harness forward-facing seat, high-back booster and backless booster
  • Can use lower anchor straps and tether to secure high-back booster
  • Two removable cupholders (nice to be able to choose space or storage)
  • Adjustable headrest and side wings
  • Blow molded plastic instead of EPS/EPP foam
  • Body cushion and harness strap covers for added comfort and ease of cleaning
  • Machine washable fabric (smooth fabric makes it easy to wipe down for smaller messes)
  • FAA approved
  • On-seat storage for instruction manual

(In all fairness, these aren’t necessarily problems but I list them here to inform potential consumers of Tranzitions SnugLock issues)

  • Back removes easily from base when not installed
  • No recline
  • Basic LATCH connectors (hook-style) are more challenging to use than Graco’s premium push-on connectors

My decision to purchase the original Tranzitions model four years ago was based on three things: price, width and harness weight limit. With the new Tranzitions SnugLock model, I still get a narrow seat with a no-rethread harness and higher weight limits, PLUS now I have the ease of a quick and secure installation using the SnugLock feature. The width of the Graco Tranzitions SnugLock 3-in-1 Harness Booster is right there, within an inch or so, with some of the most well-known narrow and very expensive car seats—but with two cup holders! If you are in the market for a no-fail installation, forward facing seat for a pre-schooler, this is the seat for you. If your child is like my daughter, the harness could last them until 2nd grade. And hey, maybe by then you’ll actually be able to drive your kid to school again! 😉


When to transition from a five point harness into a booster:

Comparing the safety of a backless booster and a high-back booster:

To learn about the blow-molding process used in the Tranzitions seat in place of EPP/EPS foam:  


Thank you to Graco for providing the Graco Tranzitions SnugLock used for this review. No other compensation was provided. All opinions expressed are those of the author.


  1. Marnie July 11, 2023
    • Kecia July 11, 2023
  2. Lianna June 20, 2022
  3. Annonymous March 21, 2021
    • Kecia March 21, 2021

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