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

Diono Connect3 R Backless Booster

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

At a glance

Fits children from 40 to 120 lb
Up to 63 in tall
Backless 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 Connect3 R Backless Booster for?

The Connect3 R Backless is a backless belt-positioning booster for children from 40 to 120 lb and 38 to 63 in, according to its manual. It is used only with a vehicle lap and shoulder belt and a red shoulder belt guide strap. It is not certified for aircraft and expires over eight years from purchase.

Reasons to consider it

One booster for children from 40 to 120 lb
A red guide strap to position the shoulder belt
Armrests that lock on, and lap belt guides on both sides
Diono lists it at 16.3 in wide and 4.85 lb, with 2 cup holders included

Things to weigh up

The child's ears must be below the top of the raised vehicle seat or headrest
No LATCH; secure it with the belt even when empty
Not certified for aircraft
Expires over eight years from the date of purchase

My take on the Connect3 R Backless Booster

It suits an older child who fits a booster and sits in a vehicle seat with a headrest tall enough to keep the ears below its top. The trade-off is that it has no backrest, so the vehicle seat or headrest has to do that job, and the manual describes no LATCH connectors. The Connect3 R 2-in-1 shares the same manual and limits but adds a removable backrest with a height adjuster and a two-position recline.

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 Connect3 R Backless 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.

Backless booster40 to 120 lb · 38 to 63 in: Only the base is left, so the vehicle seat has to support the child’s back and head, and the belt guide sits at the hip.

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

What are the Connect3 R Backless Booster weight, height and age limits?

Diono Connect3 R Backless Booster limits by mode
Mode	Child weight	Child height	Minimum age	Conditions
Backless booster	40 to 120 lb	38 to 63 in	Not published	Child's ears must be below the top of the fully raised vehicle seat or headrest

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

Connect3 R Backless Booster specifications

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

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 to know before you live with it

Fitting the belt correctly

Place the booster flat on the vehicle seat bottom, touching the seat back. Pull the shoulder belt guide strap from its storage underneath and feed it between the backrest mounting bar and the seat base. Buckle the vehicle belt with the lap portion in both lap belt guides, low on the hips and not over the belly. Tighten by pulling the shoulder belt upward, then attach the red guide to the shoulder belt and adjust the strap so the guide sits just above the shoulder. The shoulder belt must not touch the neck or pass over the armrest.

Source: Diono Connect3 R Backless manual (PDF)

Which vehicle seats work

The manual allows only a lap and shoulder belt. Lap-only, motorized, dual retractor, inflatable and door-mounted belts are excluded, so choose another seat if those are present. It must not go in a rear-facing or side-facing vehicle seat, or in front of an active front air bag. Because it is backless, the vehicle seat or headrest has to reach above the child's ears. Check that the shoulder belt retracts properly before each use. If the vehicle buckle is pulled across the lap belt guide, the manual says to use a different seating position.

Source: Diono Connect3 R Backless manual (PDF)

Armrests, cover and cleaning

The left and right armrests click into their slots with the waffle pattern facing out, and the manual says they cannot be removed afterward. The seat cover comes off by pulling its elastic loops over the tabs around the shell. Remove the seat cushion before washing and do not wash the foam. Machine wash the cover separately in cold water on a gentle cycle, or hand wash, and dry flat away from direct sun, with no bleach, iron or dry cleaning. Spot clean the shell. The cup holder is dishwasher friendly and stores under the seat.

Source: Diono Connect3 R Backless manual (PDF)

Is the Connect3 R Backless 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

Connect3 R Backless Booster: common questions

What are the Connect3 R Backless booster limits?

The manual says to use it only with children from 40 to 120 lb and 38 to 63 in. The child's ears must also be below the top of the fully raised vehicle seat or headrest.

Diono Connect3 R Backless manual (PDF) (opens in a new tab)

Does the Connect3 R Backless use LATCH?

Its manual does not describe LATCH connectors and says to secure the booster with the vehicle belt even when unoccupied. The Connect3 RXT Backless manual includes LATCH/UAS connectors.

Diono Connect3 RXT Backless manual (PDF) (opens in a new tab)

How is it different from the Connect3 R 2-in-1?

Both are covered by the same manual. The 2-in-1 is listed for 40 to 120 lb and 38 to 63 in, the same limits as the Backless. It adds a backrest with a headrest and backrest height adjuster and a two-stage recline, and it can be used backless once the backrest is removed.

Diono support: Connect3 boosters (opens in a new tab)

Is the Connect3 R Backless approved for airplanes?

No. The manual says it is not certified for aircraft because aircraft seats lack the shoulder belt it needs.

Diono Connect3 R Backless manual (PDF) (opens in a new tab)

When does the Connect3 R Backless expire?

The manual says not to use it once it is over eight years from the date of purchase.

Diono Connect3 R Backless manual (PDF) (opens in a new tab)

How big is the Connect3 R Backless booster?

Diono lists it at 9.1 in tall, 16.3 in wide, or 19.7 in with cup holders, 15.4 in deep and 4.85 lb.

Diono support: What is the narrowest booster Diono offers (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
Connect3 R Backless Booster (this seat)	120 lb	—	—	8 years
Connect3 R 2-in-1 High-Back 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
Monterey 6DXT SafePlus High-Back Booster	120 lb	—	—	8 years
Solana Backless Booster	120 lb	—	—	8 years
Solana 2 Backless Booster	120 lb	—	—	8 years