Fitting three car seats across the back seat might seem impossible at first, but with the right setup, it can absolutely be done. Every family’s needs are a little different, so your best solution will depend on your kids’ ages, whether they are rear-facing or forward-facing, and the size and layout of your vehicle. Some cars and car seats are more three-across friendly than others, but with a little planning and careful installation, even small vehicles can work.
When shopping for seats that fit well side by side, look for models that advertise being narrow. Installing with the vehicle seat belt instead of the LATCH system can also give you more flexibility to position the seats closer together. If you are using an infant car seat, installing it without the base using the seat belt can help save valuable space. In this guide, we’ll highlight our top picks for fitting three across, along with key features to keep in mind.
Our Top Picks:
The Clek Liing is a top-tier infant car seat designed with safety, comfort, and style in mind. Made in Canada by a team with roots in the automotive world, it brings some seriously smart safety features to the table—like a metal load leg to help reduce crash forces and rigid LATCH connectors for a rock-solid installation. The base offers seven recline options to help you get the right angle no matter what kind of back seat you’re working with, whether flat or sloped. Its slim, compact design also makes it a great pick for smaller cars or tight front-to-back spaces.
Now upgraded with a zip-off seat cover for easier cleanups, the Liing is built for real-life convenience. It includes a two-stage infant insert to support your newborn from day one, plus an extra-large canopy with SPF 100+ protection, ventilation, and a peek-a-boo window. You’ll also get wide stroller compatibility using Maxi-Cosi-style adapters. Fabrics range from cozy jersey knit to water-repellent Crypton to breathable Merino wool, and all are free of brominated and chlorinated flame retardants. Every Liing is made in Canada and recyclable through Clek’s own program.
Perfect If:
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You need to fit three car seats across.
The Clek Liing is one of the top choices for tight backseats. Its slim profile makes it perfect for three-across setups, especially when installed with the vehicle seatbelt. -
You drive a compact car or have tall front-seat passengers.
Its compact front-to-back design means more legroom for those up front and a better fit in smaller vehicles. -
You’re preparing for a very small baby.
Whether you’re expecting twins, a premature baby, or just want the best fit for a tiny newborn, the Liing is ready. The harness adjusts as low as 4 inches, and the infant insert provides extra support and head positioning for the smallest passengers.
Things to Know:
The Clek Liing delivers excellent safety features and a space-saving design, but there are a few considerations:
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It is not the lightest infant car seat. If you plan to carry it frequently or have a long walk from the car to your home, the weight could matter.
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For even more space savings, you can install the Liing without its base using the seatbelt. This makes it even more compact and ideal for tight backseats.
At a Glance:
- Carrier weight: 9 lbs (not including infant insert)
- Base weight: 17 lbs
- Dimensions: 26.8″ H x 27.7″ L x 16.9″ W
- Width: 16.9″
- Base dimensions: 22.6″ L x 13.2″ W
- Baby height limit: 32″
- Baby weight limit: 4-30 lbs
- Type of harness: Rethread
- FAA Approved: Yes
- European seat belt routing option: Yes
- Installation method(s): Rigid LATCH with base / seat belt with base / European belt path with carrier only
- Load Leg: Yes
- Expiration: 9 years
- Warranty: Limited lifetime warranty
The Britax Poplar S is a convertible car seat designed for families who need both space efficiency and easy installation. Its compact profile makes it a strong option for smaller vehicles or situations where you need to fit three seats across. Britax’s patented ClickTight system takes the guesswork out of installation. Simply open the seat, thread the seatbelt, and close it. The built-in tensioner secures the belt for you, creating a tight and safe install without requiring extra strength.
Although it measures just 17 inches wide, the Poplar S still offers impressive comfort and safety. It allows rear-facing use up to 50 pounds and converts to forward-facing as your child grows. The 14-position headrest and no-rethread harness make it easy to find a secure, comfortable fit, while the removable infant insert provides extra support for smaller babies. Safety features include the ReboundReduce steel stability bar, a V-shaped tether, a steel-reinforced frame, and a SafeCell crumple zone for added protection in a crash. The seat’s naturally flame-retardant fabrics, machine-washable cover, and dishwasher-safe cup holders help make everyday use easier for parents.
Perfect If:
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You have a smaller vehicle or need to fit three car seats across.
The Britax Poplar S’s slim 17-inch width makes it a smart choice for compact backseats or families needing to fit multiple car seats across one bench. -
You want a car seat that’s quick and easy to install.
The ClickTight system, built-in seat belt lock-offs, and color-coded guides simplify installation with either LATCH or a seat belt. -
You prefer a seat with strong safety features.
Britax’s steel-reinforced frame, energy-absorbing base, and V-shaped tether provide extra protection and peace of mind. -
You want a seat that supports extended rear-facing.
Your child can be up to 49 inches tall or 50 pounds (whichever comes first) and still ride rear-facing.
Things to Know:
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The Britax Poplar S can be used from birth, but some parents find the infant inserts don’t provide the best fit for very small newborns. If you’re skipping the infant seat stage, check the newborn fit first to make sure it works for your baby’s size.
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Fixed headrests in your vehicle could interfere with forward-facing installation, so check your car’s compatibility in advance.
At a Glance:
- Car seat weight: 28 lbs
- Dimensions: 23.5″ H x 20.5″ L/D x 17″ W
- Width: 17″
- Rear-facing weight and height limit: 5-50 lbs; up to 49″
- Forward-facing weight and height limit: 22-65 lbs; up to 49″
- Highest harness slot height: 18″
- Type of harness: No Rethread
- FAA Approved: Yes
- Installation method(s): Seat belt install (preferred) / LATCH*
- Three across friendly: Yes
- Expiration: 10 years
- Warranty: 1 year
*LATCH Weight Limit: 35 lbs
The Britax One4Life Slim is one of the easiest car seats to install, which makes it a stress-free option for both parents and grandparents. With Britax’s ClickTight® installation system, securing it with a seat belt takes very little effort. Simply lift the seat panel, thread the belt, pull the slack tight, and close the panel. There is no need to wrestle with the seat or handle tricky locking clips, so even caregivers who may not have a lot of physical strength can get a safe, snug fit. Since proper installation is key to protecting your child, ClickTight helps make sure you get it right every time.
Although it is packed with safety features and can accommodate higher weight limits, the One4Life Slim still measures just 17.5 inches wide. This narrow size works well in smaller vehicles and makes it easier to fit three seats across a single row. It also grows with your child, offering one of the tallest harness heights at 19 inches, which is perfect for taller kids who are not yet ready to move out of a harness. With its space-saving design, impressive safety engineering, and ability to serve your family for years, the One4Life Slim is a smart choice for households with limited space or more than one child in car seats.
Perfect If:
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You have a taller child who needs extra room to grow.
The One4Life Slim offers one of the tallest harness heights available at 19 inches, an inch or two more than most convertible seats, making it a strong choice for kids who outgrow other seats too quickly. -
You want an easy, secure installation every time.
Britax’s ClickTight technology makes installing this seat with your vehicle’s seatbelt quick and almost foolproof. -
You need a seat with a built-in seat belt lock-off.
This feature is especially useful for older vehicles without locking seatbelts or when traveling internationally, helping keep the seatbelt firmly in place. -
You’re looking to fit three car seats across.
At just 17.5 inches wide, the One4Life Slim is narrower than the original 19.5-inch version, offering more space-saving options for tighter backseats, though three-across still requires careful measuring and planning.
Things to Know:
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The One4Life Slim may not work well in vehicles with non-removable headrests, especially in forward-facing or booster modes. Compatibility varies by car model.
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Its narrow design, while great for tight spaces, might feel snug for children with broader builds as they grow.
At a Glance:
- Car seat weight: 24.7 lbs
- Dimensions: 18.5″ x 17.5″ x 24.5″
- Width: 17.5″
- Rear-facing weight and height limit: 5-50 lbs; 18-49″
- Forward-facing weight and height limit: 30-65 lbs; 35-49″
- Booster weight and height limit: 40-120 lbs; 44-63″
- Highest harness slot height: 19″
- Type of harness: No Rethread
- FAA Approved: Yes
- Installation method(s): Seat belt (preferred) / LATCH*
- Three across friendly: Yes
- Expiration: 10 years
- Warranty: 1 year
*LATCH Weight Limit: 35 lbs Rear-Facing / 40 lbs Forward-Facing
The Clek Foonf is an excellent choice for families who want top-notch safety, durability, and a modern look. Built with a strong steel and magnesium frame, energy-absorbing foam layers, and an anti-rebound bar, it offers superior rear-facing protection. The seat supports extended rear-facing use up to 50 pounds and provides plenty of legroom for growing kids. Its REACT Safety System uses aluminum honeycomb technology to absorb crash forces, similar to your vehicle’s safety features. For forward-facing installation, the Foonf includes a rigid LATCH system, which is rare and adds both safety and ease of use by making installation secure and straightforward.
At just 17 inches wide, the Foonf is one of the narrowest convertible seats available, making it a smart pick for fitting three across. It also sits higher in the vehicle, giving children a better view out the window and potentially reducing strain for parents when buckling and unbuckling. The new zip-off fabric covers make cleaning quick and easy, a helpful feature for busy families. Overall, the Foonf combines safety, style, and peace of mind in one premium Canadian-made car seat.
Perfect If:
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You need to fit three car seats across.
At just 17 inches wide, the Foonf is one of the narrowest convertible seats available. Integrated seat belt lock-offs help secure a tight installation even in tight spaces. -
Your vehicle has non-removable or angled headrests.
The Foonf works well with fixed or forward-tilting headrests that can challenge other seats. -
You want to use a convertible seat from birth.
Adding the Infant-Thingy insert (sold separately) allows the Foonf to fit newborns safely and snugly. -
You prefer natural materials.
Clek’s fabrics contain no added flame-retardant chemicals, offering a more chemical-conscious option without sacrificing safety. -
Your child loves a good view.
The Foonf’s elevated design gives little riders a better view out the window.
Things to Know:
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Installing the Foonf in the center seat can block your rear window view due to its tall profile.
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The seat is heavy because of its sturdy steel-reinforced frame. It’s not ideal if you need to move it often between vehicles.
At a Glance:
- Car seat weight: 38 lbs (rear-facing); 33 lbs (forward-facing)
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Dimensions:
- Rear-facing dimensions: 25.5-28.5″ H x 13-17″ W x 33″ L
- Forward-facing dimensions: 28-32.5″ H x 13-17″ W x 17.5″ L
- Width: 17″
- Rear-facing weight and height limit: 14-50 lbs; 25-43″ (or with “infant thingy” from 5 pounds and 19″)
- Forward-facing weight and height limit: 22-65 lbs; 30-49″
- Highest harness slot height: 17″
- Type of harness: Rethread
- FAA Approved: Yes
- Installation method(s): Seat belt (preferred) / LATCH* (can do rigid LATCH and seat belt together when forward facing)
- Three across friendly: Yes
- Expiration: 9 years
- Warranty: Lifetime Extended Warranty
*LATCH Weight Limit: 25 lbs Rear-Facing / 35 lbs Forward-Facing; LATCH and vehicle belt installation (used in combination) for children weighing 22-65 lbs
The Clek Fllo is a strong alternative to the Foonf, offering many of the same high-level safety features in a smaller, lighter package. Like the Foonf, it has a steel and magnesium frame, energy-absorbing foam, and supports extended rear-facing use up to 50 pounds. It also uses Clek’s aluminum honeycomb technology to absorb crash energy and reduce impact on your child. With a narrow width just under 17 inches, the Fllo fits well for three-across seating in smaller cars.
Unlike the Foonf, the Fllo does not include a built-in recline or rigid LATCH system. However, it sits lower in the vehicle, which some parents find easier for loading and unloading. The anti-rebound bar is available separately and adds extra stability when rear-facing. Like all Clek seats, the Fllo is made in Canada and comes with flame-retardant-free fabric options and zip-off covers for easy cleaning. If you want a more compact and budget-friendly option that still delivers excellent safety, the Fllo is a great pick.
Perfect If:
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You like the Clek Foonf but need a slightly smaller seat.
The Fllo is about 1.5 inches lower in the vehicle and a bit more compact overall. Plus, its anti-rebound bar is optional, which can help with fitting in tighter spaces. -
You need to fit three car seats across.
At just 17 inches wide, the Fllo is one of the narrowest convertible seats available. Built-in seat belt lock-offs make installation tight and secure, even in cramped spots. -
Your vehicle has non-removable or angled headrests.
The Fllo works well with these tricky headrest setups where other seats might struggle. -
You want to use a convertible seat from birth.
Adding the Infant-Thingy insert (sold separately) provides a snug and safe fit for newborns and smaller babies. -
You prefer more natural fabrics.
Clek’s flame-retardant-free materials offer a chemical-conscious option without compromising safety.
Things to Know:
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The Fllo is lighter and more affordable than the Foonf, but it lacks the Foonf’s built-in recline. You may need to use a rolled towel to get the right rear-facing angle.
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It does not have the advanced rigid LATCH system found on the Foonf. This might actually be a benefit if your car’s seating position doesn’t support rigid LATCH well.
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These differences come with the advantage of a smaller, lighter seat that fits better in tighter spaces.
At a Glance:
- Car seat weight: 25 pounds (28 pounds with anti-rebound bar)
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Dimensions:
- Rear-facing dimensions: 23.5-27″ H x 13-17″ W x 32.5″ L (29″ L without anti-rebound bar)
- Forward-facing dimensions: 26-31″ H x 13-17″ W x 24″ L
- Width: 17″
- Rear-facing weight and height limit: 14-50 lbs; 25-43″ (or with “infant thingy” from 5 pounds and 19″)
- Forward-facing weight and height limit: 22-65 lbs; 30-49″
- Highest harness slot height: 17″
- Type of harness: Rethread
- FAA Approved: Yes
- Installation method(s): Seat belt (preferred) / LATCH*
- Three across friendly: Yes
- Expiration: 9 years
- Warranty: Lifetime Extended Warranty
*LATCH Weight Limit: 35 lbs Rear-Facing / 40 lbs Forward-Facing
The Peg Perego Viaggio Shuttle Plus 120 is a high-back booster built for safety, comfort, and lasting use. It offers three adjustable zones—the headrest, upper backrest, and side wings—so the seat adapts as your child grows while providing strong side impact protection. When your child is ready, the backrest can be removed to convert the seat into a no-back booster, making it more portable.
A rigid LATCH system makes installation simple and secure. Peg Perego’s Blind Lock system helps prevent accidental unbuckling by passengers. The seat features an aluminum-reinforced backrest, EPS foam padding, and an ergonomic design for top safety and comfort. Finished with premium Italian fabrics and a built-in cup holder, the Shuttle Plus 120 combines style and security. At 17.25 inches wide, it is a smart choice for fitting three boosters across.
Perfect If:
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You need to fit three boosters across.
At just 17 inches wide, the Shuttle Plus 120 Booster is slim enough for tight backseat spaces, making it a great choice for families who need multiple seats side by side. -
You have a tall child.
The adjustable backrest and height limit of 63 inches provide one of the tallest booster fits available, ideal for kids who need extended booster use.
Things to Know:
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The Shuttle Plus 120 is a true booster seat without a built-in harness, relying entirely on your vehicle’s seat belt to keep your child secure.
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Even if your child meets the size requirements, they need the maturity to sit properly every time—no slouching, leaning, or unbuckling.
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Booster seats are as much about behavior as size, and most children are ready for a true booster around age six or older.
At a Glance:
- Car seat weight: 14 lbs
- Dimensions: 26″ H x 17.25″ L x 17″ W
- Width: 17.25″
- Weight and height limit: 40-120 lbs; 39-63″
- Type of harness: No harness
- FAA Approved: No
- Installation method(s): rigid LATCH
- Three across friendly: Yes
- Expiration: 12 years
- Warranty: 2 years
Installation Tips for Fitting Three Car Seats Across
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Start with the middle seat
The middle spot is usually the narrowest, so placing the most compact seat there frees up space on the sides. -
Put rear-facing seats in the middle
Rear-facing seats are taller and take up more front-to-back space. Centering them can maximize room for forward-facing seats or boosters on either side. -
Use the seat belt instead of LATCH when possible
Seat belts often offer more flexibility in positioning than LATCH connectors, which can make a big difference in tight spaces. -
Try installing infant seats without the base
If your infant seat allows it, installing without the base using the seat belt can save valuable inches. -
Test different seat arrangements
Sometimes switching seat positions is all it takes to make three across work. Don’t hesitate to try a few combinations before settling on the best fit.
If your current seats don’t fit three across, don’t worry! You don’t need a new car. Investing in three new, narrower seats designed for tight spaces is much more affordable. We’re also here to help you solve your personal car seat puzzle!
Three-Across Installation Checklist
After you find a setup that fits, it’s essential to double-check that every seat is installed safely and correctly. Here’s what to watch for:
✔ Secure and Independent Installation
Each car seat should be firmly installed on its own. It should not move more than one inch side-to-side or front-to-back at the belt path.
✔ Proper Seat Alignment
Make sure each seat stays aligned with the vehicle’s seat belt or lower anchors. Neighboring seats shouldn’t push any seat out of place.
✔ Correct Lower Anchor Use
If you’re using lower anchors, they must be straight across the seat. Avoid mixing anchors from two different seating positions unless your vehicle’s manual says it’s allowed.
✔ One Anchor per Connector
Each lower anchor connector should attach to only one designated anchor point unless otherwise directed by your vehicle manual.
✘ No Overlapping or Pressing
Seats can fit closely together, but they should never physically overlap or press into each other. Avoid bending or distorting any seat to make it fit.
✘ No Warping or Damage
Check that no part of any car seat is bent, warped, or misshapen. Every seat should stay in its original form and function.
✘ No Belt or Strap Interference
Seat belts and lower anchor straps should not interfere or rub against each other. Make sure seat belt buckles remain easily accessible and can fasten securely.
Three-Across FAQs
Is it better to skip the infant car seat and go straight to a convertible to save space?
It depends on what you need. Infant seats are usually smaller, easy to carry, and click in and out without waking your baby. They also work with strollers, which is super handy for quick trips. If space is tight, installing an infant seat without the base takes up the least room front to back. On the other hand, slim convertible seats grow with your child and stay installed, but they aren’t as portable. Also, not every convertible fits newborns perfectly, so double-check the harness height and fit before buying.
Can I make an infant car seat more compact by removing the base?
Absolutely! Most infant seats can be installed without the base, which saves a lot of space. Some, like the Nuna PIPA Urbn, don’t even need a base at all.
Can I fit three car seats across in a small car?
It’s tricky but doable. Look for seats labeled “three-across friendly” or those that are especially narrow. You’ll probably need to use seat belts instead of LATCH for one or two seats to squeeze them all in.
How do I know if a car seat will fit in my car before I buy?
Check the seat’s dimensions on the manufacturer’s website. If you can, try installing a demo seat in your car—at a store like Bambi Baby, for example. Some brands also have online fit guides or tools.
Are smaller car seats less safe?
Not at all! All car seats sold in the U.S. meet strict safety standards. Compact seats often have the same safety features as bigger ones—like rigid LATCH, load legs, side-impact protection, and energy-absorbing foam.
What if my car has a sloped or oddly shaped back seat?
Look for seats with multiple recline options or leveling feet. These features help get the right angle even on uneven seats.
Are convertible and all-in-one seats safe for newborns?
Some are, but not all. If you skip the infant seat stage, make sure your convertible has a low harness position, proper recline, and infant inserts designed for tiny babies.
What’s the difference between all-in-one and convertible seats?
Convertible seats switch from rear-facing to forward-facing. All-in-ones add booster mode too, so they can be used from birth up to big kid years. Just keep in mind many families still get a separate booster later on.
When should I switch from rear-facing to forward-facing?
Experts recommend keeping your child rear-facing as long as possible, until they reach the seat’s rear-facing height or weight limit. Many modern all-in-ones allow rear-facing up to 40 or even 50 pounds.
Questions?
Strolleria is dedicated to making the baby gear buying experience less overwhelming for parents. If you have more questions about the best three-across car seats, feel free to contact us at cs@strolleria.com.
