REASONS TO BUY
Better crash test results
REASONS TO AVOID
Very wide
Awkward headrest
Hard to carry
Diono Monterey 4DXT Review
While the crash test results are impressive, it doesn't offer much and might be too wide for some cars or family requirments
Credit: Abriah Wofford
Our Verdict
The Diono Monterey 4DXT is not our favorite booster seat, and for the price, we kind of expected it to score higher overall compared to the competition. While the crash test results are good and better than most, we think it is lacking in ease of use, comfort, and quality. It is a larger seat that is super wide, and the width made it harder for little ones to reach around and find the vehicle buckle. If you don't need to carry it or fit multiple seats in one car, the size and awkward carry might be acceptable, but it doesn't do anything particularly well beyond the crash test results. We think there are better options with more to offer that might save you some money.
Editor's Note: The Diono Monterey 4DXT was tested and compared to a new lineup of boosters on January 26, 2024.
Compare to Similar Products
 This Product
Diono Monterey 4DXT | |||||
|---|---|---|---|---|---|
| Awards |  Best Booster for Most |  Best Booster for Travel and Carpooling |  Best Booster on a Budget | ||
| Price | $200 List | $160 List $159.99 at Amazon | $40 List $37.98 at Amazon | $120 List $79.99 at Amazon | $29 List |
Overall Score  |
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| Star Rating | |||||
| Bottom Line | This option is super wide and might be a struggle with multiple kids across one row, so despite the better crash results it wasn't a favorite | Great choice for most families with better crash testing analysis, easy installation, and cozy seating for kids | Great for travel and carpooling, but the quality and crash results make it less appealing as an all-the-time booster | A comfy headrest and good crash test results make this lightweight choice an option that won't break the bank | This basic booster offers disappointing results in most metrics, including crash test analysis, making the low price less appealing |
| Rating Categories | Diono Monterey 4DXT | Chicco KidFit Zip A... | BubbleBum | Diono Cambria 2 | Graco TurboBooster... |
| Crash Test (35%) | |||||
| Ease of Use (25%) | |||||
| Weight/Size (15%) | |||||
| Comfort (15%) | |||||
| Quality (10%) | |||||
| Specs | Diono Monterey 4DXT | Chicco KidFit Zip A... | BubbleBum | Diono Cambria 2 | Graco TurboBooster... |
| Modes | High Back Booster, Backless Booster | High Back Booster, Backless Booster | Backless Booster | High Back Booster, Backless Booster | Backless Booster |
| High Back Booster Weight Range | 40-120 lb | 40-110 lb | N/A | 40-120 lb | N/A |
| High Back Booster Height Range | 38-63 in | 38-57 in | N/A | 38-63 in | N/A |
| Width | 20.7 in | 18.2 in | 11.3 in | 19.9 in | 16.3 in |
| Weight | 17.9 lb | 11.8 lb | 0.9 lb | 12.0 lb | 4.5 lb |
| Backless Booster Height Range | 38-63 in | 38-58 in | 40-57 in | 38-63 in | 43-57 in |
| 5 Point Harness Weight Range | N/A | N/A | N/A | N/A | N/A |
| 5 Point Height Range | N/A | N/A | N/A | N/A | N/A |
| LATCH Equipped | Yes | Yes | No | Yes | No |
| #REF! | #REF! | #REF! | #REF! | #REF! | #REF! |
| Recline Positions | None | 2 | N/A | None | N/A |
| Foam Type | EPS + EPP | EPS | None | None | None |
| Seat Lifespan | 8 Years | 8 Years | 4 Years from purchase date | 8 Years | 10 Years |
| Aircraft Certified |
Show full specification details ▼Hide full specification details ▲
Our Analysis and Test Results
Diono began in Seattle, Washington, in the late 90s. Shortly after launching, they won an award that inspired them to make more safety seats and to start a branch in England. They went on to launch the first steel-reinforced folding seat. To increase growth and continue designing innovative safety seats, Diono accepted investment from Winona Capital in 2015.
Performance Comparison
The Monterey performed well in our commissioned crash test with MGA Research. This third party, hotter than the federal guidelines testing, resulted in one of the highest analysis results.
Credit: GearLab & MGA Research
Crash Test
The Monterey managed to outperform other Diono boosters we tested with a higher-than-average result that puts it in the top tier of results.
This analysis of the combined sensor data from the HIC and chest clip sensors indicates a potential for an additional margin of safety over the average seat.
All of the options in this review should pass federal guidelines and are considered safe. However, we ran our test a bit faster and used a stiffer sled to mimic late-model vehicles. We hoped to identify those seats that perform better than the rest. The Monterey offered some of the best HIC and chest clip sensor results in the lineup with lower recorded g-forces, where lower is better.
The Monterey shoulder positioner is easy enough to thread, but as you raise the headrest, it can bring the belt closer to the passenger's neck.
Credit: Abriah Wofford
Ease of Use
The Monterey is not that easy to use and scored below average for the group. This booster was significantly harder than most to get the belt buckled because of the width and the shape.
Our tester and helping adult struggled to get the seat out of the way to reach the buckle, and it was made all the more difficult with a child in the seat. The shoulder positioner works well, but as you extend the headrest up, it could bring the belt closer to the passenger's neck.
Installing the seat was also not straightforward with hook LATCH connectors and trouble getting the strap snug as the back wings collided with the vehicle seat. We got it done, but it wasn't user-friendly at all, and it really should have been since it was just securing the booster to the car.
The Monterrey has dual cup holders that slide out from the seat bottom and our Thermos test bottle fits in without room to spare.
Credit: Abriah Wofford
The Monterey has two slide-out cup holders you might not even notice. We like that they can be folded in for space since the seat is already so wide, and we like that our test water bottle fit.
WHile the Monterey is heavier than the average booster, you can remove the back to make it lighter for occasional travel.
Credit: Abriah Wofford
Weight and Size
This seat is heavy for a booster and is more comparable to the convertible car seats we've tested. It weighs 17.9 lbs, which is above the average for the group.
The width is also somewhat prohibitive, depending on your situation. At 20.7 inches wide, there aren't many that are wider. Not only is this a potential challenge for multiple seats across, but it can also make accessing the buckle for little ones more of a challenge as it can cover the area kids need to reach.
The Monterey has adjustable side wings to help find a good fit for most kids.
Credit: Abriah Wofford
Comfort
Comfort is not a strong suit for the Monterey compared to the competition. It scored below average in this metric and was not a preferred option by our kid testers. The comfort padding reminds us of packing material, and it has little give or bounces back when you press on it. While it is marginally better than hard plastic, it isn't great. Our kid tester likened it to “hard wood” when sitting in it.
The headrest on the Monterey is wider than average and could cause neck pain if the passenger's head falls at a harsh angle while napping.
Credit: Abriah Wofford
The fabric feels soft at first and our little tester really liked it. However, we suspect over time, it might lose this smooth and soft feeling as things can get caught in the weave. We didn't like it as much at the end of testing as we did in the beginning.
The headrest has a weird design shape, and there is a bump in it that results in the child's head jutting forward and resting at an odd and uncomfortable angle. We could get this shape to change, and it is either an intentional choice to a quality control issue, but either way, we suspect it will impact the comfort of longer drives.
We kind of like the slide-out cup holders on the Monterey, and you might even miss them if you don't know they are there.
Credit: Abriah Wofford
Quality
The quality performance of the Monterey is slightly above the average for the group. While it might not have giant red flags, for the price, we'd want more. The padding overall is lacking in makeup and placement. The fabric might be soft, but the cover is friction-fitted into a slot on the torso area of the booster, and it has hook and loop (Velcro) connections in other areas. It is generally average compared to other boosters and is neither exceptional nor hugely disappointing.
Other than a better crash test analysis result, we didn't find much to love in the Monterey and think there are likely better options for most families.
Credit: Abriah Wofford
Should You Buy the Diono Monterey 4DXT?
While the Monterey has a cool look and feel, and we get the appeal when you take a first look, it didn't impress enough in testing to make it a stand-out option in our minds. In fact, other than better crash test analysis results than much of the group, it didn't fare well in our other performance metrics like ease of use or comfort. While crash testing is important, to be sure, in this lineup, you can find other options with better crash test analysis, higher metric scores overall, and cost less. Because there are better options, we think there are better options out there.
What Other Booster Seat Should You Consider?
One of the best options in the group is the Chicco KidFit Zip Air Plus 2-in-1. This booster is less expensive than the Monterey, and it has better crash test analysis results. It also has higher-than-average results in all of the remaining metrics. We love the ease of use and the leg lounger feature for added comfort. If you want the best crash test results, the Peg Perego Viaggio Flex 120 is also one to consider. While the Peg is one of the higher-priced options in the group, it performed very well in all metrics and is a standout no matter what your booster goals might be (outside of travel).
Manufacturer Video
—
Juliet Spurrier, MD & Wendy Schmitz
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