Booster seat requirements in Washington
A car seat or booster until age 16.
Unless the child is at least 57 inches (4 ft 9 in) tall, which ends the requirement whatever their age.
- Rear facing until
- 24 months
- Back seat until
- age 13
- Seat belt alone from
- age 16
Every figure on this page was read at RCW 46.61.687 on 4 October 2026. Read the statute
What the Washington booster seat law says
The stages below are separate rules in the statute, not one rule in steps. The back seat requirement and the restraint requirement are different obligations, and a child can be caught by both at once.
| Rule | Figure | What Washington requires |
|---|---|---|
| Rear facing | under 24 months | Until 24 months (2 years). |
| Car seat or booster | under 16 years | Until age 16, unless the child is at least 57 inches (4 ft 9 in) tall. |
| Back seat | under 13 years | Required for a child under age 13. |
| Adult seat belt alone | from 16 years | Lawful from age 16, or once the child reaches 57 inches (4 ft 9 in). |
| Penalty | no figure | No amount recorded. Condition A traffic infraction under chapter 46.63 RCW. The restraint statute itself sets no amount. The jurisdiction must dismiss the notice of infraction if the driver presents proof within seven days of acquiring an approved child restraint system or booster seat and has not previously had a violation of this section dismissed. |
Size ends the requirement, whichever comes first. A child who is at least 57 inches (4 ft 9 in) tall is out of the booster in Washington whatever their age. A child who has not reached that stays in one until age 16. The size is an escape from the age rule rather than a second thing that also has to be true.
Where this and size guidance disagree, follow the stricter one. A belt that crosses the neck rather than the middle of the chest is worse protection than a booster even where the statute allows it.
The statute
Washington sets this in RCW 46.61.687. Read it at the source.
This is information, not legal advice. A city or county in Washington can set a stricter rule than the state one, and an officer enforces the text of the statute rather than a summary of it. Where this page and the statute differ, the statute is right and this page is a bug.
Where this comes from
- Statute
- RCW 46.61.687
- Source
- app.leg.wa.gov
- Jurisdiction
- Washington (WA), state law only
- Last reviewed
- 4 October 2026 0 days ago
- Read at the statute
- 4 October 2026
- Signed off by a person
- Not yet
- Amendment history
- 2019 c 59 ยง 1, effective 1 January 2020