It is no easy feat to fit three children in the backseat! Often, parents of triplets (or three children of multi-age) worry about how they will safely fit all of their children in a small car. Rather than spending tens of thousands of dollars on a new vehicle, a better (and far less expensive) option is to look into purchasing a set of narrow high back booster seats. That way, all three of your little ones can sit together comfortably and safely in the small car that you already own!
The Best Narrow High Back Booster Seat with 5 Point Harness
What is a narrow highback booster?
A narrow highback booster seat is a child safety seat that helps position your older child in a car. Seating in a typical car is designed for an adult. For a child to safely sit in such seats, they need to be positioned correctly, even when they have outgrown a typical car seat. For this reason, high back boosters are used for positioning.
How to Safely Install a Highback Booster Seat
Is there a narrow booster seat that will fit three across?
Of course! All of the boosters listed here should fit three across in most cars. All of these slimline high back booster seats measure 20” across or less.
How do I know if my child is ready for a narrow 5 point harness booster?
If your child is over two years old and over 22 lbs they can sit in one of these narrow highback boosters.
Younger and smaller children should not be in a booster just yet.
If your child is between ages 2 and 5, they likely need to use the 5 point harness feature.
After that, the booster can be used as a seat belt positioner until the weight or height limit is hit!
Best Narrow Booster Seat
We have looked at all of the options available and selected the best narrow booster seats (and they all have 5 point harnesses!). Check out our comprehensive reviews below.
1. Graco Tranzitions 3-in-1 Harness Booster Car Seat
Graco is well known to be a top leader in car seat safety. If you are looking for a well-padded, safety tested seat for your kids, this high back booster is a solid choice.
- 19” across at widest point
- Weighs 20 lbs
- Fits children 22-100 lbs
- 3 seats in 1: 5-point harnessed front facing car seat, highback belt-positioning booster and backless booster
- Engineered & crash tested to meet or exceed US standard FMVSS 213
- Converts from 5-point harnessed car seat to highback belt-positioning booster to backless booster
- Harness System adjusts the height of your harness and headrest, in one motion, to ensure that your child is always properly secured
The Transition 3-in-1 is easy to install and should fit three across in most cars. One nice thing about this seat is how easy it is to clean. You can wash the cover and replace it without any fuss or trouble threading the straps, which saves you time!
- Two cup holders
- 8 position adjustable headrest
- Side impact tested
- Lightly padded, not super comfy
- 3-in-1 harness booster helps protect your child, from toddler to youth
- Grows with your child from forward-facing harness (22-65 pounds) to highback booster (40-100 pounds) to backless booster (40-100 pounds) to continue to meet industry standards, we have increased the weight minimum from 30 to 40 pounds
- No-rethread simply safe adjust harness system allows the headrest and harness to adjust together in one motion.Do not use bleach
- Lightweight, portable seat is ideal for busy, active parents
- One-hand, 8-position adjustable headrest grows with your child
2. Cosco Finale DX 2-in-1 Booster Car Seat
This seat was specifically designed by Cosco to fit three across in most cars, making it nearly guaranteed to work well for your family.
- 18.25” across at widest point
- Weighs 11.5 lbs
- Fits children 30 – 100 lbs
- 5-point safety harness up to 65 pounds.
- Belt-positioning booster, covered up to 100 pounds
- Deluxe fabric
- Excellent for families who are always on the go
The Finale is a lightweight high back booster designed to work for your child for many years. It can easily be moved from car to car (no need to buy an extra seat for your second car or babysitter), and it has special fabric to make the ride more cozy for your kids. As a bonus, this seat comes in four cute colors for your children to choose from!
- Very affordable
- Lasts from 2 years to 100 lbs
- Made in the USA
- Not very padded
This high back booster should last you for many years, and the one year warranty has got you covered for any manufacturing defects. Amazon and Target offer free shipping on this seat, and free returns just in case it doesn’t work out!
- Extended Use: Forward-facing with harness 30-65 pounds and Belt-positioning Booster 40-100 pounds
- Designed to fit 3 across in most vehicles - Great for growing families and car pools
- Lightweight and easy to move from car to car
- Deluxe fabric gives kids a comfy ride
- Dishwasher-safe cup holder detaches for use on either side of seat
3. Disney KidsEmbrace Harness Booster Car Seat
Looking for something a little different to get your fussy kid to enjoy a car ride? This Disney high back booster chair is made just for you.
- 19.5” across at widest point
- Weighs 17.6 lbs
- Fits children 22-100 lbs
- Disney characters and superheros designed that kids want to stay in!
- Harness system features Energy Absorbing Technology.
- Contoured seat with extra padding provides support and comfort
- Trim cover is machine washable
You probably haven’t seen a seat quite like this before! Designed to entice your child into enjoying their seat, it comes in a variety of disney characters and superheros. Don’t let the fun design fool you though. This high back booster is safety tested, likely to fit three across in your car, and well made to last for years.
- Cute and fun designs
- Cape blanket included
- Three position headrest for comfort
- Two position crotch belt for perfect sizing
- Child may outgrow the character before the seat limits
You can score this seat on Amazon for a decent price, even though it is more expensive than the others on our list. Don’t forget, they offer free shipping and returns!
- 5-POINT HARNESS SECURITY: Two position points at each shoulder, two position points at the child's hips, and one point where the harness buckles between the legs to give your child the best possible protection
- 3 HARNESS POSITIONS: There are three slots to position the harness shoulder straps depending on the age and height of your child. Shoulder straps should be at or just above the shoulders whenever using a forward-facing car seat
- 2-MODE OPTIONS: This forward-facing five-point harness car seat is made for children weighing 22-65 lbs & 29”-49” tall. Converts to a belt-positioning booster seat for children weighing 40-100 lbs and 38”-57” tall
- RECOMMENDED USE: We recommend using the 5-point harness to the maximum recommended weight and height before using this car seat as a belt-positioning booster
- SAFETY CERTIFICATIONS: This seat exceeds Federal Motor Vehicle Safety Standards (FMVSS 213). Side Impact Tested only when used with a 5-point harness. Insurance Institute for Highway Safety "Best Bet" rating when used as a belt-positioning booster
4. Cosco Highback 2-in-1 Booster Car Seat
This Cosco seat has been a top contender on the market for several years. Now that there is a newer model (reviewed above), you can find the 2-in-1 at a deep discount. If you are looking for a narrow high back booster that won’t cost you much even when you need to buy three, this might be a good choice for you.
- 18.75” across at widest point
- Weighs 10 lbs
- Fits children 22 – 80 lbs
- LATCH equipped and features a 5-point harness that can be adjusted from the front.
- Two options for threading the vehicle seat belt
- Machine washable seat fabric
- removable and dishwasher-safe cup holder
This 2-in-1 will easily fit three across in practically any car. At under 19” wide, it is the narrowest seat on our list. If you have a compact car, the Cosco might be your best bet. It will also fit well in an airplane, if you often travel. Not only will this work well with your growing child, but the entire cover can be thrown in the washing machine, making it easy to clean as well.
- Latch system equipped
- Machine washable fabric
- Limited weight range
If you look around, you can find this seat for under $55 in certain colors, and Amazon offers free shipping and a one year warranty.
- KEEP KIDS SAFE THROUGH TWO STAGES - The Cosco Highback Booster car seat takes your child from 22 lbs. to 80 lbs. with its two different modes. Use the 5-point harness for smaller children and convert it to a belt-positioning booster seat as they grow.
- 2-IN-1 SAFETY SEAT - The Highback Booster is LATCH equipped and features a 5-point harness that can be adjusted from the front. As the child grows, simply remove the harness to use it as a belt-positioning booster car seat.
- SHOULDER BELT GUIDES - While in belt-positioning booster seat mode, the shoulder belt guides provide parents with two options for threading the vehicle seat belt to give children of different heights a better fit.
- MACHINE WASHABLE SEAT FABRIC -Messes happen. When they do, you can easily remove the seat pad and clean it in a washing machine and dryer.
- REMOVABLE AND DISHWASHER-SAFE CUP HOLDER - The removable and dishwasher-safe cup holder allows for easy cleanup of spills.
5. Evenflo Maestro
This Evenflo seat has a lovely design and is made by a company well known for its rigorous safety testing.
- 19” across at widest point (and only 17” if you don’t use the cupholders!!)
- Weighs 14.2 lbs
- Fits children 22 – 110 lbs
- Auto-adjust belt path correctly positions the seat belt to your child for a proper fit
- 4 shoulder harness positions and 2 crotch buckle positions for extended use
- Integrated cup holders keep drinks close without increasing the width of the car seat
- Meets or exceeds all applicable federal safety standards and Evenflo’s side impact standards.
The Maestro is a rare find! Both affordable and slim, it should fit three across in nearly any backseat. This seat is also unique in that it fits children up to 110 lbs, giving it the biggest weight range on our list. You will literally get years of use out of this seat, and likely never have to buy another car seat again!
- Stylish, high end design look
- Easy to adjust harness
- Latch or tether options
- Safety tested to over 2X industry standard
- Huge weight range
- Latch is hard to take out
If you are looking at a Clek car seat, and you need to save some cash, the Fllo is a good choice. Don’t overlook the fact that this seat can be used for 4+ years, which will save you money in the long run.
The Maestro comes with a warranty to cover any defects, and you can score a good deal at both Target and Amazon, with free shipping from both sites!
- This 2-in-1 Combination Booster Car Seat fitting children from 22-110 lbs. converts from a 5-point harnessed car seat to belt-positioning booster allowing for extended use as your child grows
- The Maestro Harness Booster Car seat helps protect harnessed children from 22-65pounds and belt-positioned children from 40-110 pounds. Harnessed booster age: At least two years of age. Seat belt booster age:At least four years of age
- In case of the 5 point harness , the featured height recommendation is 71 to 127 centimeters (28 to 50 inches) and tops of the child’s ears are at or below the top of the child restraint headrest . In case of the belt positioning booster , the height recommendation is given by 110 to 145 centimeters (43.3 to 57 inches) and tops of the child’s ears are at or below the top of the child restraint headrest
- Designed and tested for both Side Impact and Structural Integrity at energy levels approximately 2 times the Federal Crash Test Standards to keep your child safe
- Integrated cup holders keep drinks close without increasing the width of the car seat, allowing multiple car seats to fit your back seat.Once your child has reached 40 lbs. and at least 4 years of age, you may transition to the booster version of this seat with your vehicle's seat belt
If you need a narrow high back booster seat with 5 point harness, you can’t go wrong with any of the seats on the list! Overall, both the budget seats and the more expensive seats will get the job done. It just depends on what features your family needs. If you are looking for the best narrow high back booster seat with 5 point harness, any of these seats would be an excellent, safe, and comfortable choice!