When it comes to keeping children safe in cars, parents usually focus on extended rear facing (ideally until their kids are at least 4 or 5). However, while the lion’s share of car seat safety comes from rear-facing as long as possible, keeping children boostered safely until they’re physically and physiologically capable of using seat belts is an essential part of child car safety. A child boostered until s/he no longer needs a booster seat (which typically isn’t until 10 to 12 for most kids) faces a much lower risk of suffering potentially fatal injuries in crashes than children who are prematurely seat belted.

However, not every parent has the budget for the best booster seats on the market (e.g., seats like the Clek Oobr, Maxi-Cosi RodiFix, and Peg Perego Viaggio Flex 120 high back boosters). Today we’re going to look at a good booster seat on a budget, the Diono Monterey XT High Back Booster. It’s made by Diono, a company that will always have a soft spot in my heart for coming out with the second and third 50-pound convertible car seats in the US (one of which, the Diono Rainier, is still one of the best choices on the market for extended rear-facing).

The Monterey XT is one of the best high-back/backless boosters at or around the $100 mark; let’s see how it compares to the high-end high-backs in keeping kids safe.

Diono Monterey XT – What’s the big deal?

The Diono Monterey XT is a high-back/no-back booster seat by American car seat maker Diono; it’s essentially a combination of the high-back portion of the original Diono Monterey and the backless segment of a fellow Diono high-back booster, the Cambria. Its special features include a highly adjustable headrest and adjustable-width side wings to accommodate kids of varying sizes, lower LATCH anchors, retractable cup and snack holders, and thick, durable, and easily cleanable foam padding for additional comfort. Additionally, as a dual stage booster, it can be converted from a high-back to a backless booster in a few minutes.

Beyond its features, the Monterey XT remains a high-back booster, which makes it the next step after your child stops rear-facing (which you’ll ideally do until 4 or later, as in Sweden) or forward-facing. A booster seat like the Monterey XT is designed to keep your kids safely restrained until they’re old enough to use adult seat belts without car seats (which occurs when kids can pass the 5-step test, which is usually not before ages 10 to 12). Functional and affordable, the Monterey XT is a good budget high-back booster seat. It is made in China.

Diono Monterey XT Limits for Weight and Height

High-back booster:  40 to 120 pounds. The height range spans 38 to 63 inches and the highest belt guide position stops at 22 inches. Per best practices, neither infants nor toddlers should ever be placed in booster seats (they need to be rear-facing), but children from 4-5 years old are potentially safe booster candidates depending on maturity. Most 4-year old preschoolers will be safer rear-facing than being boostered, but exceptionally responsible 5-year olds can be boostered if you can no longer rear-face them. On the other hand, if you feel your kids aren’t yet ready for a booster seat at that age, you’re fine waiting until they’re 6 or 7. It depends on your child; children in Sweden are typically boostered at 4-5 once done rear-facing and are expected to sit safely. The country has the lowest rates of child auto deaths on Earth.

Backless booster: 40 to 120 pounds. The height range is the same as that in the high-back mode at 38-63 inches. Best practices suggests sticking with high-back boosters until children are at least 8 before switching to backless boosters since younger children are more likely to move their heads out of safe positions when falling asleep than older ones.

Headrest support: Whether you use the Monterey XT in high-back or backless mode, it needs to be installed on a vehicle seat that includes a head rest (unlike a seat like the Peg Perego Viaggio Flex 120, which does not require vehicle head rests).

Outgrown: The Monterey XT can no longer be used either when the weight, height, or manufacturing expiration limits are reached, or when the tops of your child’s ears surpass the booster’s head rest when fully raised or your vehicle’s head rest in its fully raised position.

Buy the Diono Monterey XT on Sale at Amazon here.

Dimensions and Key Features of the Diono Monterey XT

The Monterey XT is 17 inches wide at the base. When the wings are retracted, it is 17 inches across at the shoulders; when they are extended into wide mode, the seat becomes 20 inches wide at the expandable back. The seat pan depth remains constant at 14 inches. When the cup and snack holders are expanded, the seat becomes a whopping 23 inches wide. With the head rest fully extended, the Monterey XT is 29.5 inches tall, and it weighs 13.9 pounds in high-back mode.

Its narrow width at 17 inches makes it a good choice for 3 across car seat installations with narrow booster seats, although it will not be as narrow as boosters like the Clek Oobr and Peg Perego Viaggio Flex 120, each of which take up as little as 14 inches across. The Monterey XT has a rather short 6 year lifespan; this is less than the original Monterey’s 8 year expiration timeframe. Expiration is based on the date of manufacture; you can find this information beneath the seat as well as the model and serial numbers. As with every other booster seat on the market, the Monterey XT is not airplane compatible, per the FAA, since it relies on a lap and shoulder belt, and airplanes are equipped solely with lap belts.

Using the Diono Monterey XT (Seat belt installation and additional FAQ)

Installation: Installation is rather straightforward. All you need to do is sit the booster on your vehicle’s seat, connect the lower LATCH anchors, thread your vehicle’s seat belt through the XT’s belt guide and click it into the stalk. You can set it up in a few seconds each time. You don’t need to use the lower LATCH anchors, but if you do, they secure the booster seat to your vehicle so you don’t need to buckle it in all the time. You’ll still need to buckle your child in (or have your child buckle himself or herself in) each time s/he uses the seat.

As a bonus, the Monterey XT is one of a few booster seats (and car seats in general) compatible with inflatable seat belts. However, it’s important to note that you need a vehicle head rest behind the Monterey XT each time you use it, regardless of which kind of seat belt you have. Additionally, the XT needs to sit flush against the back of the vehicle’s seat. To put it another way, if the booster slopes forward due to the vehicle’s head restraint, you can’t use the Monterey XT with that vehicle.

Child fit: Because of its wide weight and height range, flexible width adjustment system, and 22 inch belt guide height limit (one of the largest on the market), you’re going to be able to fit nearly all kids of booster age in the Monterey XT. You’ll find a large red and white dial behind the seat that you can twist to adjust the width of the seat by changing the side wings. Per the manual, you’ll want to adjust them until your child is comfortable. The internal space ranges from 12.5 to 14.5 inches. The head rest is adjustable in 11 steps, allowing a booster guide position range from 15.5 inches to 22 inches. To adjust the head rest, you need to squeeze the red handle behind it and pull it up or down.

Cup holders: While I’m generally against cup holders in car seats due to the copious research connecting extensive snacking to childhood and adult obesity, I realize they’re popular with a number of parents and children here in the US. There’s a space for a cup and a space for a snack on each side; both sets of cup holders are retractable, and the width of the XT balloons from 17 inches to 23 inches depending on whether or not they’re in use. It’s worth noting that most European car seats (including booster seats for older children) don’t include cup holders; the RodiFix is a good example.

Why Buy the Diono Monterey XT?

In conclusion, for a $100 booster seat, the Monterey XT is hard to beat; it’s a safe way for parents to transport children once they’ve finished extended rear-facing (or forward-facing if they were turned forward before 5) in a minivan, SUV, truck, or car. You can keep your kids in the Monterey until they are physically and physiologically ready to move from booster seats to the adult seat belt (typically between ages 10 and 12 for most kids).

The Monterey XT is narrow enough to be a 3-across car seat friendly booster seat while having enough room in height, weight, and overall dimensions to potentially be one of the only two or three car seats your child will ever need (along with a convertible car seat like the Diono Rainier for the first five years). The biggest downside to it is its too-short 6 year expiration date, but for a seat this cheap, you can afford to buy another, and another, and another to keep your kids safely boostered until they’re ready for seat belts.

You can buy the Diono Monterey XT in 4 colors: Heather (black/grey), Purple, Red, and Teal here. Canadians, it’s unfortunately not readily available, but you can buy an equivalent seat, the Britax Parkway SGL 1.1, here.

If you find my information on best practices in car and car seat safety helpful, you can do your shopping through this Amazon link. Canadians can  shop here for Canadian purchases. Have a question or want to discuss best practices? Join us in the forums!