The Complete List of Slim & Narrow Car Seats for 3-Across

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.