Slim and ultra-narrow car seats are a hot trend right now. And while this new trend has been a godsend for many parents and caregivers looking to squeeze 3-across in their vehicle, it’s quite possible that the looming side-impact standard (FMVSS 213a), which will take effect on June 30, 2025, will force the discontinuation of some narrow harnessed car seats that aren’t able to comply with the stringent new requirements. Or, manufactures may be forced to redesign headwings and/or add large, external side-impact “pods” to existing seats to get them to pass this new federal standard.
These enhancements might have the unintended consequence of making slim and narrow car seats significantly wider. Time will tell, but the threat is real and we all need to pray that we don’t lose the majority of our current selection of narrow car seats for the sake of progress in safety standards.
With that said and prayers sent, we created this list as a resource for parents searching for a slim car seat. We included measurements, specs and MSRP quotes to help you narrow down which seats might suit your situation, and your wallet.
Some of the seats listed are “All-in-Ones” meaning that they can be used rear-facing, forward-facing and as a booster. Keep in mind that narrow car seats may not be sufficiently roomy to comfortably accommodate bigger, older children – especially for stockier kids with broad shoulders. If you buy an ultra-narrow All-in-One that is rated up to 100 lbs. (or more) in booster mode, just be realistic about your expectations.
A seat that is only 17″ wide may be perfect now but not be very comfortable down the line for an older kid who weighs 70+ lbs. There are always trade-offs. While you should buy the seat that works for your situation now and in the near future, just be aware that the upper weight range for use in booster mode (if the seat that you’re considering can be used as a booster), may not be realistic.
Slim Convertible & All-in-One Seats
| Model | Width | Specs | MSRP |
|---|---|---|---|
| Britax Poplar | 17" | RF 5-50 / FF 22-65 | $299 |
| Britax Poplar S with ARB | 17" | RF 5-50 / FF 22-65 | $349 |
| Britax One4Life Slim | 17.5" | RF 5-50 / FF 30-65 / BO 40-120 | $399 |
| Clek Fllo | 17" | RF 14-50 / FF 22-65 | $449 |
| Clek Foonf | 17" | RF 14-50 / FF 22-65 | $559 |
| Cosco Kids Scenera NEXT | 17" | RF 5-40 / FF 22-40 | $59 |
| Diono Radian 3R | 17" | RF 4-50 / FF 22-65 / BO 40-120 | $199 |
| Diono Radian 3RXT | 17" | RF 4-50 / FF 22-65 / BO 40-120 | $299 |
| Evenflo Revolve360 Slim | 16.7" | RF 4-50 / FF 22-65 | $349 |
| Graco SlimFit3 LX | 16.7" | RF 5-40 / FF 22-65 / BO 40-100 | $279 |
| Graco True3Fit LX with ARB | 16.7" | RF 5-40 / FF 22-65 / BO 40-100 | $279 |
| Safety 1st Jive | 17.5" | RF 5-40 / FF 22-65 | $109 |
| Safety 1st Ever Slim | 17.5" | RF 5-40 / FF 22-65 / Bo 40-100 | $199 |
Slim Harness/Booster Combination Seats
| Model | Width | Specs | MSRP |
|---|---|---|---|
| Chicco MyFit Harness + Booster | 17.5" | FF 25-65 / Bo 40-100 | $219 |
Slim Highback Booster Seats
| Model | Width | Specs | MSRP |
|---|---|---|---|
| Diono Connect3 R (no Latch) | 16.3" w/o cupholder | 40-120 | $109 |
| Diono Connect3 RXT (Coming Sooon) | 16.3" w/o cupholder | 40-120 | $129 |
| Peg Perego Viaggio Flex | 17.5" (adjustable) | 40-120 | $299 |
We hope this information was helpful in deciding which products might meet your needs and your budget. For more advice on fitting 3-across, check out these other insightful articles on the subject: