Learn everything you need to know about Washington State car seat laws.

The Washington car seat law is codified under RCW 46.61.687 of the state’s Child Passenger Restraint Law. The car seat laws stipulate that children up to age two must be properly secured in a rear-facing car seat, while those between 2 and 4 years must ride in a car seat with a harness. According to the law, children four and older must ride in a car or booster seat until they are 4’9″ tall. Once your child is over 4’9″, you must secure them properly with the vehicle’s seat belt. The law mandates that children below 13 ride in the back seat.

If you and your children are visiting Washington State or have just moved, you must pay attention to the laws regulating car seat use. The Department of Transport report on Washington roads revealed in 2017 that a car crash happened every 4 minutes. Therefore, you will understand why the state prioritizes car seat laws. Violating these laws attracts fines and sanctions. 

In this article, you will learn all about the car seat laws that apply to the Evergreen State and how to abide by them.  

P.S.: This is solely researched information from credible Washington State government sources and should not be interpreted as legal advice. Consult your lawyer for specific legal advice. 

Overview Of Washington State Car Seat Laws

washington state car seat law

Washington has relatively comprehensive car seat laws compared to several other states. And since the latest update in January 2020, the rules have become even more transparent and precise. Here are the basics of Washington State car seat laws:

  • All children under two years old must be in a rear-facing car seat.
  • Children aged 2 to 4 must be in a forward-facing car seat with a 5-point harness.
  • Children older than four must be in a forward-facing car seat with a 5-point harness or a booster seat—whichever is appropriate according to standard weight and height limits used by car seat manufacturers.
  • Children can graduate to adult seat belts once they’re 4’9″ tall. However, the state recommends keeping children in a booster seat until they’re 12 years of age.
  • Children with outgrown booster seats must be appropriately secured using lap and shoulder seat belts.

Types Of Car Seats According To Washington Car Seat Law

Let’s break down what type of car seat is appropriate for different age groups and how the law applies to them.

Rear-Facing Car Seats (Infant And Convertible)

Washington state requires all children younger than 2 to be buckled up in rear-facing car seats. This was part of the new law instituted in 2020 and applies to all infants from birth till they turn 2.

You have two options: an infant-only car seat and a convertible car seat:

  • An infant car seat is a detachable carrier that can be moved from the vehicle to other places, such as a stroller. It has low weight and height limits, generally around 35 pounds and 32 inches, but can easily last until your baby is two years old.
  • A convertible car seat can be used for rear- and front-facing positions and accommodate heavier children up to 50 pounds or more. You can use it in the rear when the child is younger and then convert it to a forward-facing seat as the child grows.

But don’t be eager to switch to forward-facing as soon as the child turns 2. The rear-facing position is safer for a child’s delicate neck and spine. So, it’s best to wait until the child reaches the weight or height limit required for the front-facing position.

Washington Forward-Facing Car Seat (Convertible And Combination) Laws

As your child grows, their car seat needs to change too. In Washington State, the law requires children between 2 and 4 years of age to use a forward-facing car seat. But note that this is just the minimum requirement. 

The National Highway Traffic Safety Administration (NHTSA) and the Child Safety Commission both recommend keeping your child in a forward-facing seat until they reach the maximum height or weight limit of the seat, which for most kids is around the age of 8 years.

You can continue using the convertible car seat in front-facing mode, buy a dedicated combination seat, or upgrade to an all-in-one seat.

I recommend buying a seat with high weight and height limits so your kid can use it for as long as possible. And make sure the seat has a five-point harness system for maximum security.

Washington Booster Seat (Backless And High-Back) Laws

Once your kid has outgrown the forward-facing car seat (usually around eight years of age), it’s time to graduate them to a booster seat. 

Washington state recommends that all children under 12 years use booster seats but are not legally bound to follow the rule. However, it does give the maximum height limit – the kid has to be in a child restraint until they reach 4’9″.

Your kid can use either a backless or high-back booster seat that raises the child to ensure the lap and shoulder seat belt fits them securely. Most booster seats also have adjustable headrests to support their still-growing neck and spine. Install the seat correctly and buckle up before you start driving. 

Washington Car Seat Laws For Older Children

In Washington State, child seat laws don’t apply to kids who have reached 4’9″ in height. The standard seat belt law applies at this point, meaning an adult shoulder and lap seat belt must secure every passenger.

This means after your kid has reached the maximum limit of their booster seat, they must be secured with a regular seat belt. The driver or any adult accompanying the child must secure them properly.

When Can A Child Sit In The Front Seat Of A Car In Washington State? 

Washington state also recommends that kids below 13 should always sit in the back seat. Although this is not a legal requirement, it does add an extra layer of protection from front-end collisions. 

But if you must seat them in the front, move the seat back as far as possible and turn off the airbag.

Kids have delicate bodies and cannot withstand the airbag’s impact in case of an unfortunate accident. In addition, if you’re placing kids in a car seat on the front seat, ensure it’s as far from the dash as possible.

5-Step Seat Belt Test For Teen/Tweens

This 5-step seat belt safety checklist can help ensure your kid is ready for the adult seat belt and safely buckled up before the car is in motion.

  • The kid is not slouching-has their back against the vehicle seat.
  • The shoulder belt fits snugly across the chest and mid-shoulder.
  • The lap belt is low enough, sitting on the upper thighs and hips.
  • The child can comfortably bend the knee at the edge of the seat without slouching.
  • The child can stay seated in this position for the entire duration of your trip.

If your child meets all these requirements, they are ready for the adult seat belt. Otherwise, it would be best to switch back to a booster seat until they are big enough.

Washington Car Seat Laws For Public Transport

Washington car seat law does provide some exceptions to vehicles registered as public transportation. Here’s a quick overview.

  • Taxi cab: Vehicles registered as “for hire” or “taxi” are exempt from all child seat laws. But they still must comply with the seatbelt belt law applicable to older children.
  • Buses: All public buses, shuttles, and school buses are exempt from child restraint law.
  • Ride-sharing services: Washington state doesn’t specify the safety requirements for ride-hailing services like Uber or Lyft. However, since they primarily operate as personal vehicles and are not registered in the state as public transportation, they must comply with all child restraint laws.
  • Vehicles manufactured without a seat belt: The law also gives an exception to vehicles manufactured without the factory-installed seatbelt. These are mostly the cars from before 1965 and other vehicles such as golf carts, ATVs, or executive cars. In these cases, you don’t have to buckle the kids in any car or booster seat.

Washington Car Seat Laws: Can I Leave My Child In Car? 

Concerning leaving a child in the car, the Washington child passenger safety law stipulates that children under 16 can’t be left alone.

Penalties For Violating Washington Car Seat Laws

Washington State has some of the strictest car seat laws in the country. It has a tiered penalty system for people found violating the law repeatedly.

  • The first-time offenders can choose between paying a $75 fine or attending a $25 child safety seat education class.
  • The second-time offenders must pay the $75 fine and attend the $25 education class.
  • Third-time offenders must pay a fine of up to $125.
  • The fourth-time offenders pay a penalty of up to $150.

Remember that it’s a primary violation, which means law enforcement officers can pull you over if they suspect you’re not correctly using the car seat for your children.

The Bottom Line

Washington State has done a great job in making and enforcing the car seat laws. But the responsibility to ensure our kids are safe and secure on the road ultimately falls on our hands as parents. So make sure you follow the car seat laws and use a proper restraint system for children of all ages. I strongly recommend using the 5-Point Seat Belt Test to ensure your kid is appropriately restrained in the car.


What are the booster seat requirements in Washington(W.A.) state?

Booster seat requirements for W.A. state that children older than four must be in either a forward-facing car seat with a 5-point harness or a booster seat—whichever is appropriate according to standard weight and height limits used by car seat manufacturers.

According to the law, you’re only allowed to use adult seat belts on children when they are above 4’9″ tall. Some Washington residents have expressed divergent views about this requirement because children have different growth rates. 

How does the Washington state booster seat law affect child passenger safety?

The specifications of Washington car seat laws allow children who are too small to safely use adult seat belts to be adequately secured in appropriate child restraint systems, such as booster seats. In an auto accident, these restraint systems or the child’s position in the car will reduce the crash’s impact and could save their lives. 

Where to get car seat help in Washington?

Washington State Booster Seat Coalition Stations have traffic safety experts and certified child passenger safety technicians who can help fit you and your children in the car safely. You can go to any of their stations in Washington to get a car seat inspection. 
Safe Kids Washington Stations also offer inspections. The non-profit organization educates families, raises awareness, creates safer environments, and advocates for improved laws to protect children.