Traffic Safety · Car Seat & Booster
Car Seat & Booster Laws in Washington
When your child can move from a booster to a seat belt in Washington — plus rear-facing, front-seat, and the fine, with the law kept separate from best practice.
Check your child's stage in Washington
Enter age, height, and weight. We show the Washington law separately from best practice.
4′9″ = 57 in. Enter only the boxes you have — this state uses exit at 4′9″ only — age is not a trigger, so a child under 4′9″ still needs a booster regardless of age.
Educational guide to the minimum legal requirement, not legal or safety advice. Best practice is often stricter than the law. Always follow your car seat’s manufacturer instructions, and confirm the current rule with the official source below — last reviewed 2026-07-09.
The four stages in Washington
Each rung is tagged Law or best practice.
A child under 2 must ride rear-facing, kept rear-facing until they reach the seat manufacturer’s height or weight limit.
A child under 4 who has outgrown rear-facing must ride forward-facing with a harness, to the manufacturer’s limit.
A booster or properly fitting belt is required until the child is 4′9″. The statute notes this is usually ages 8–12 — height is the only trigger, not age.
Exit rule: exit at 4′9″ only — age is not a trigger, so a child under 4′9″ still needs a booster regardless of age. The adult belt must fit — lap low across the hips, shoulder belt across the chest.
Front seat, the fine & the source
Seating rule, the exact booster logic, and any recent change.
Children under 13 must ride in the rear seat “where it is practical to do so.” This is law (RCW 46.61.687), not a recommendation.
| Booster exit logic | Height 4′9″ only (no age trigger) |
| Seat belt OK | Once 4′9″ and the adult belt fits correctly |
| First-offense fine | No set statutory amountnot fixed in statute RCW 46.61.687 orders a “notice of traffic infraction” but fixes no dollar figure. The ~$136 figure often quoted comes from the court penalty schedule, not the statute. |
| Statute | RCW 46.61.687 |
Washington’s current rules took effect January 1, 2020 (SB 5407): rear-facing to 2, harness to 4, booster to 4′9″, rear seat under 13. Older "age 6 / 60 lb" descriptions are pre-2020 and outdated.
What Washington parents get wrong
Washington rewrote its child-passenger law effective January 1, 2020 (SB 5407), and any summary describing "age 6 or 60 lb" is quoting the old, repealed version. The current law legislates rear-facing under 2, a harness under 4, and — distinctively — a booster until the child reaches 4′9″. Washington is the only state whose booster exit is height-only: age is not a trigger, so a 10-year-old under 4′9″ still legally needs a booster, and the statute itself notes this is usually ages 8–12. Front-seat placement is real law here (under 13 in the rear "where practical"), unlike the states that only recommend it. One honesty note: RCW 46.61.687 does not set a dollar fine — the ~$136 figure comes from the court penalty schedule, not the statute.
Common questions
When can a child stop using a booster in Washington?
When they reach 4′9″. Washington uses height only — age is not a trigger — so a child under 4′9″ still needs a booster even past age 8. The statute notes this is usually ages 8–12.
Does Washington require rear-facing car seats by age?
Yes. A child under 2 must ride rear-facing, kept rear-facing to the seat manufacturer’s height or weight limit.
Do children have to ride in the back seat in Washington?
Yes, it is law: children under 13 must ride in the rear seat where it is practical to do so (RCW 46.61.687).
What is the fine for a car-seat violation in Washington?
The statute sets no dollar amount — it orders a notice of traffic infraction. The ~$136 figure often quoted comes from the court penalty schedule, not RCW 46.61.687 itself.
Not legal advicePlainStatute provides plain-language summaries of public law for general information only. This is not legal advice. Statutes change; always confirm current requirements with the official source linked above before acting.