Diono Monterey Booster Review


Diono Monterey (Formerly Sunshine Kids Monterey): A Versatile Booster

Vehicle seat belts are designed to fit an average 160 lbs. man, not your average 4-10 year old child.  That’s why we have booster seats.  A booster seat raises the child up so that the lap portion of the lap/shoulder belt falls across the bony hips, not the soft, easily injured abdomen.  High back boosters, like the Sunshine Kids Monterey, have headrests with shoulder belt guides to keep the shoulder belt off the child’s neck.  Booster seats should always be used with a lap/shoulder seat belt.

Who should use this seat?

Diono (formerly Sunshine Kids) recommends this seat for children who are about 4-10 years old, weigh 30-120 lbs., and are between 38″ and 63″ tall.  The back can be removed and used for children who fit the same size specifications.  Some booster seats require a 40 lbs. minimum when switching to backless, but not the Monterey.  As a technician, I would never recommend a child under 40 lbs. use a backless booster.

My opinion? This seat has great safety and comfort features and is designed to grow with a child.

Choosing which seat to use should be based on many factors, including the way the seat fits in your vehicle, how the child fits in the seat, and, in the case of a booster, the maturity of the child.  Because boosters allow more freedom of movement, the child must have the maturity to sit correctly in the seat without wiggling out of the seat belt or slouching.  Only you can determine if your child is mature enough, but we generally see this maturity blossom around age 4.  Also, a child under 40 lbs. is best protected by a seat with a 5-point harness.  I was very pleased to read in the Monterey’s instruction manual that Sunshine Kids agrees, “IMPORTANT: Children who weigh 40 lbs (18kg) or less are best protected in a 5-point harness restraint.  Sunshine Kids Juvenile products* recommends that children remain in a 5-point harness restraint until reaching the maximum weight or height allowed.”


The Monterey requires minor assembly and comes in 2 pieces: backrest and base.  Most boosters that come with removable backs require that the backs be attached, so I was prepared for that.  The backrest has hooks that clip onto the base securely.


Features include:

*deep EPS foam in the headrest (EPS foam is the stuff bicycle helmets are made of), in the torso wings, and on the hip area of the arm rests for side impact protection

*EPE foam in the seating area for comfort

*supportive headrest

*width-adjustable torso wings

*stowable deep cup holders on both sides of the base

*wide seat for larger children

*deep seat for long-legged children

*attaches to vehicle with LATCH (called ISOFAST connectors)


The instruction manual is one of the more disorganized booster manuals I’ve read, and I’ve read a lot.  All of the illustrations are up front instead of embedded with the text.  That makes the text difficult to understand.  For someone who is experience with booster assembly, it won’t make much of a difference, but for someone new to boosters, it may be frustrating to read the instructions.

Cover and padding

There are four covers available for the Monterey: gray, red, black, pink.  The cover for the headrest and side trims is a comfortable microfiber with a breathable mesh inside.  The cover is thick and comfy.  It’s attached with elastics and plastic fasteners.  The cover can be handwashed and line dried when necessary.

Installation and use

Boosters are very easy to use: just plop them on the seat and buckle the child in with the vehicle belt.  The Monterey is a bit different because of the ISOFAST connectors.  The booster weighs in at a hefty 15.5 lbs. on my scale and Sunshine Kids recommends LATCHing the booster in when lower LATCH anchors are available.  If they aren’t available, the seat is still safe to use.  LATCHing the booster also helps ensure that the booster won’t become a projectile in a crash.  It won’t install as tightly as a car seat will; the main purpose of LATCHing it is to stabilize it while the child climbs into it and to keep it from becoming a projectile.  To attach the seat using the ISOFAST connectors, find your lower LATCH anchors in your vehicle, attach the connectors, then pull the strap at the bottom front of the base to tighten.  To loosen, lift up on the lever under the strap and pull the base away from the vehicle seat.

When buckling a child into the Monterey, the shoulder belt must be routed through the red open-loop design shoulder belt guide.  This is easily done just by sliding the belt into the guide.  The open-loop design means that the shoulder belt won’t get caught on it if the child leans forward; in the Monterey, the shoulder belt will remain snug on the child.  The lap belt should fit under the arm rests, snugly over the child’s thighs and hips; again the belt path is marked in red.

The back of the Monterey should be adjusted so that the shoulder belt guides are slightly above the child’s shoulders.  To adjust the height of the back, simply squeeze the red handle on the back of the headrest and lift up.  There are 11 height adjustments from which to choose.  At the highest setting, the shoulder belt guide is around 21+/-” (depends on who you ask).  Even though we have side curtain air bags, I do prefer my son to have the safety of a highback booster with EPS foam in the headrest.  A major study showed that highback boosters are beneficial in side impacts over backless boosters: www.eurekalert.org/pub_releases/2005-09/chop-htb090905.php .

Airplane use and expiration

Because the Monterey doesn’t have an internal harness, it cannot be used on an airplane and is not FAA-approved.  The back can be removed and packed into a large suitcase while the base can be carried by the child as a carryon, or the base can be used as a backless booster on a trip.  The Monterey expires after 6 years from when it was manufactured.


The Monterey sells for $120-$140, depending on where you can find it, cheaper online, of course.  For the money, you get a solid booster that doesn’t need a high vehicle seatback or vehicle head restraint behind it (some other manufacturers’ highback boosters do), it has EPS foam in all the important areas, it’s width adjustable to fit growing children, it converts to a backless booster, and it has LATCH.  For my money, I think that’s pretty good value for what you get.

The not-so-good

The plastic fasteners holding the cover on are nearly impossible to remove.  It was quite a workout for me to remove the fasteners so I could remove the cover to wash it, and I needed a flat screwdriver to pry them up before using a needlenose pliers to remove them.  The LATCH/ISOFAST strap is short, which allows the connectors to slide into the base as you move the seat outside the vehicle.  It can be difficult to fish one connector out if it’s stuck inside the base.

The final word

My son is really likes his Monterey.  He feels comfy in it and I like the adjustability and versatility.  Don’t forget that booster use is very important until a child fits in the vehicle belt.  Here’s a wonderful 5-step test from SafetyBeltSafe USA, www.carseat.org, to determine if your child is large enough to fit a vehicle belt alone without a booster, usually around ages 9-10:

1. Can the child sit with his bum all the way back against the vehicle seat?

2. Do the child’s knees bend easily at the edge of the vehicle seat?

3. Does the shoulder belt fit across the collarbone and not the child’s neck?

4. Is the lap belt low over the child’s hips?

5. Is the child able to stay like this for the entire trip?

If you answered “no” to any of the above questions, your child still needs a booster, just like my 9 yr old 90th percentile for height, 75th percentile for weight son does.


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