Diono does not sell this seat on Amazon. See its own site for photos.

Diono Monterey 6DXT SafePlus High-Back Booster

A high-back booster seat with one mode: high-back booster 40 to 120 lb, 38 to 63 in.

At a glance

Fits children from 40 to 120 lb
Up to 63 in tall
High-back booster only
8-year usable life

Not sold on Amazon

Diono lists this seat on its US site. Buy from Diono or an authorized retailer, and confirm the exact model number before you buy.

Diono product page Manual

Specifications checked against Diono’s US site and manual on September 17, 2026. Not hands-on tested. How I research

Who is the Monterey 6DXT SafePlus High-Back Booster for?

The Diono Monterey 6DXT SafePlus is a folding high-back booster for children 40 to 120 lb and 38 to 63 inches tall. It uses the vehicle lap and shoulder belt, can attach with LATCH straps, comes with a Side Impact Management Pod and backpack carry straps, has no backless mode, and expires 8 years after purchase.

Reasons to consider it

A Side Impact Management Pod that clicks onto the door side of the seat
Carry straps for wearing the folded booster on your back
Adjustable LATCH straps, which Diono recommends when the car has lower anchors
A folding lever that clicks to lock the seat open or closed

Things to weigh up

The pod has to sit on the door side, placed so it would hit the door rather than the window glass
Carry straps are only for a folded seat, and not for anyone with back, shoulder or neck problems
Not usable with lap-only, dual retractor, inflatable, motorized or door-mounted belts
Diono does not publish its width or weight on the support page

My take on the Monterey 6DXT SafePlus High-Back Booster

The 6DXT suits a family that wants the folding Monterey 6 booster plus a way to carry it on their back between cars. The trade-off is that the side pod goes on one side only and must face the door, and the seat never becomes backless. It shares its manual and limits with the 6XT SafePlus; the extras the manual marks as 6DXT only are the pod and the carry straps.

A research summary of Diono’s published specifications and manual, read October 7, 2026. Not a hands-on test or a crash-safety rating.

Who the Monterey 6DXT SafePlus High-Back Booster fits

This seat covers one stage. Diono gives it a 8-year life from the date of manufacture, so check the date label before using a hand-me-down.

High-back booster40 to 120 lb · 38 to 63 in: The seat’s own back and belt guide route the vehicle belt across the shoulder, and the sides give the child something to lean on when they sleep.

A school-age child with a backpack beside an empty high-back booster

What are the Monterey 6DXT SafePlus High-Back Booster weight, height and age limits?

Diono Monterey 6DXT SafePlus High-Back Booster limits by mode
Mode	Child weight	Child height	Minimum age	Conditions
High-back booster	40 to 120 lb	38 to 63 in	Not published	—

A child must meet every limit for the mode they use. The labels on your seat and its manual are the final word.

Monterey 6DXT SafePlus High-Back Booster specifications

Seat weight: Not published
Width: Not published
Usable life: 8 years
Aircraft use: Not certified for aircraft

How the Monterey 6DXT SafePlus High-Back Booster installs

Lower anchors: LATCH/UAS connectors. Check your vehicle manual for which seating positions have anchors, and switch to the seat belt once the child passes the anchor weight limit in the manual.

Every install is a fit between one seat and one vehicle. Read both manuals, and use a free inspection station if anything is unclear.

An empty car seat installed on a back seat, seen through an open car door

Will it fit your car?

Diono does not publish a width for this seat, so measure your back seat and compare it with the seat in a store before buying.

Check your vehicle manual for lower anchor positions and any head-restraint rules.
Rear-facing seats need front-seat room: try the install behind the driver before you commit.
Not certified for aircraft use: plan on gate-checking it or using a different seat to fly.

What features does the Monterey 6DXT SafePlus High-Back Booster have?

LATCH/UAS connectors

What to know before you live with it

Fitting the Side Impact Management Pod

The pod is listed as included with the 6DXT only. The manual says to place it on the side of the booster next to the vehicle door, positioned so it would hit the door, not the window glass. You insert its mounting pins into the slots on the side of the seat, pressing firmly on the top and then the bottom until you hear a click. To remove it, you grip it firmly and pull it away from the seat. The manual describes it as additional side impact protection; Diono publishes no test data for it in the manual.

Source: Diono Monterey 6DXT SafePlus manual (PDF)

LATCH straps and the belt fit

With the seat on its side, you press the silver cam lock and pull out both LATCH connectors, attach the far one first, then push the booster back and tighten each adjuster strap in turn. A gap behind is acceptable if the head support touches the vehicle seat back or headrest. For the child, the shoulder belt guide goes at least 1 cm above the shoulders, the lap belt through both lap belt guides, and the buckle should line up with the grey belt path guides. The manual says never to lock the retractor and to leave a switchable one in ELR mode.

Source: Diono Monterey 6DXT SafePlus manual (PDF)

Folding and carrying it as a backpack

You squeeze the folding lever to fold the seat and listen for the click that confirms it is locked. The carry strap hooks attach to the top and bottom loops on the back, a slider adjusts the fit, and the straps store in a compartment on the back of the seat. The manual allows the straps only on a folded booster. Fabric care matches the 6XT: remove and do not wash the memory foam, machine wash the cover cold on a gentle cycle, dry it flat away from direct sunlight, and spot clean the shell.

Source: Diono Monterey 6DXT SafePlus manual (PDF)

Is the Monterey 6DXT SafePlus High-Back Booster recalled?

No campaign in the current NHTSA child-restraint data names this model family, and I have not run a separate review for it. Check your seat’s model number and date of manufacture before use.

NHTSA recall search · Recent car seat recalls

Monterey 6DXT SafePlus High-Back Booster: common questions

What comes with the Monterey 6DXT SafePlus?

Diono lists the booster, the instruction manual, a registration card, two cup holders, a Side Impact Management Pod and backpack carry straps.

Diono support: Monterey 6XT and 6DXT SafePlus (opens in a new tab)

Which side does the 6DXT side impact pod go on?

The side next to the vehicle door, positioned so it would hit the door rather than the glass. It clicks into slots on the side of the seat.

Diono Monterey 6DXT SafePlus manual (PDF) (opens in a new tab)

What are the Monterey 6DXT weight and height limits?

The manual allows children who weigh 40 to 120 lb and are 38 to 63 inches tall, restrained only with the vehicle lap and shoulder belt.

Diono Monterey 6DXT SafePlus manual (PDF) (opens in a new tab)

Can the Monterey 6DXT fit 3-across?

Diono says the 6XT and 6DXT fit 2-across in most cars and that each vehicle is different. It does not publish a width figure for these seats on the support page, so I would check the space in your car.

Diono support: Monterey 6XT and 6DXT SafePlus (opens in a new tab)

Is the Monterey 6DXT approved for airplanes?

No. The manual says it is not certified for use in aircraft, because aircraft seats do not have the shoulder belt it needs.

Diono Monterey 6DXT SafePlus manual (PDF) (opens in a new tab)

Answers refer to the model and manual version on this page. Check the instructions supplied with your seat.

Before you buy

Weigh and measure your child. The limits above are the manufacturer’s, and a child has to meet all of them for the mode they will use.
Confirm the exact version. Colors, retail exclusives and model numbers change limits more often than you would expect.
Read the manual before you buy, not after. It is linked above and holds the fit rules, the install methods and the expiry.
Check recalls by model number and date of manufacture, and register the seat with Diono so you hear about the next one.

Sources

Other Diono booster seats

Model	Top child weight	Seat weight	Width	Usable life
Monterey 6DXT SafePlus High-Back Booster (this seat)	120 lb	—	—	8 years
Connect3 R 2-in-1 High-Back Booster	120 lb	—	—	8 years
Connect3 R Backless Booster	120 lb	—	—	8 years
Connect3 RXT 2-in-1 High-Back Booster	120 lb	—	—	8 years
Connect3 RXT Backless Booster	120 lb	—	—	8 years
Cambria 2 2-in-1 High-Back Booster	120 lb	—	—	8 years
Cambria 2XT 2-in-1 High-Back Booster	120 lb	—	—	8 years
Everett NXT High-Back Booster	120 lb	—	—	8 years
Monterey 2XT 2-in-1 High-Back Booster	120 lb	—	—	8 years
Monterey 4DXT 2-in-1 High-Back Booster	120 lb	—	—	8 years
Monterey 5iST FixSafe High-Back Booster	120 lb	—	—	8 years
Monterey 6XT SafePlus High-Back Booster	120 lb	—	—	8 years
Solana Backless Booster	120 lb	—	—	8 years
Solana 2 Backless Booster	120 lb	—	—	8 years