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Britax Willow S

The Britax Willow S rear-faces up to 30 lb, is 16.9 in wide, and has an expiration of 6 years, per Britax.

  • $279.99List price
  • 30 lbRear-facing to
  • 16.9 inWidth
See it on Britax's site

When does it expire?

Follow Britax

All infant car seats

Willow S: key facts

  • The Britax Willow S rear-faces from 4 to 30 lb and 17 to 32 in tall, per Britax.
  • Outgrown by height: "when the top of child's head is at least 1 in (2.5 cm) below the top edge of head restraint"
  • It installs with ClickTight belt install of Alpine base (lap-shoulder belt), lap belt (with base), lower anchor attachments (with base), lap-shoulder belt (without base, American belt path), lap-shoulder belt (without base, European belt guide) or lap belt (without base).
  • Britax says it expires 6 years after the date of manufacture.
  • Britax lists it as certified for aircraft ("When installing baseless: This restraint is certified for use in motor vehicles and aircraft. When installing with the base: This restraint is not certified for aircraft use, because the aircraft belt is not compatible with this child restraint base.").
  • It's 16.9 in wide at the widest point.

From Britax's manual and published specs. Always follow the limits on your seat's labels.

How the Willow S stacks up

Against the 74 infant car seats we track. The shaded band is where the middle half of them fall; the dot is this one.

Expiration6 years

Within the typical range for infant car seats (6 years to 8 years).

This one
6 yearsmiddle 7 years10 years
Rear-facing limit30 lb6th highest rear-facing limit of 73

The same as most infant car seats (30 lb).

This one
22 lbmiddle 30 lb35 lb
Width16.9 in7th narrowest of 41

Within the typical range for infant car seats (16.9 in to 17.5 in).

This one
14.8 inmiddle 17.3 in19 in
Price$279.9922nd lowest price of 58

Within the typical range for infant car seats ($219.99 to $449.99).

This one
$74.99middle $329.99$850

What sets the Willow S apart

Measured against the 74 infant car seats we compare, from each maker's published specs.

  • 7th narrowestof the 41 infant car seats with it published: 16.9 in

Next to its closest matches

Strollers named with the Willow S

6 strollers on Cribpicks are named with the Willow S in a maker's fit list. Listed stroller fit: Select Britax strollers (Britax compatibility chart: https://us.britax.com/support/instructional-videos-and-user-manuals/compatibility-charts).

StrollerHow it is listed
BOB Alterrain ProWith the Single Jogging Stroller Adapter for Select Britax Infant Car Seats with ClickTight
Britax Brook+Named by Britax
Bugaboo Fox 5 RenewWith the Fox 5 Renew Car Seat Adapters
Mockingbird Single (original)With the Car Seat Adapter
Mockingbird Single-to-Double (original)With the Car Seat Adapter
Mockingbird Travel StrollerWith the QuickConnect Car Seat Adapter

Matched by brand and model name. Fit can depend on the model year, so check yours with both makers.

Flying with the Willow S

Britax's label: “When installing baseless: This restraint is certified for use in motor vehicles and aircraft. When installing with the base: This restraint is not certified for aircraft use, because the aircraft belt is not compatible with this child restraint base.” It is 16.9 in wide at its widest point.

What airlines say about car seats:

  • American: “Each ticketed customer is allowed 1 stroller and 1 car seat to be checked free of charge” “If an unoccupied, adjoining seat is not available, the gate agent will check the safety seat to your final destination.” Source
  • Alaska: “We will transport your child's car seat and stroller free of charge as checked baggage.” Source
  • JetBlue: “Checking a child safety seat will not count towards your checked baggage allowance and there is no fee assessed” Source
  • Spirit: “One (1) car seat will be accepted per child as checked baggage at no charge.” Source
  • Frontier: “strollers and car seats can be checked for free.” Source
  • Allegiant: “There is no charge for checking or gate checking one car seat per fare-paying passenger.” Source
  • Breeze: “Child seats may be carried on board the aircraft if a seat has been purchased for the Infant or Child” Source

Quoted from each airline's page as of 2026-11-02.

Where to buy the Willow S

Prices and availability change. We may earn a commission from some links.

good to know
  • Check for recalls: Search the agency's recall list with the model number and date code from the label: NHTSA recall search.
  • Car seat use and installation: see NHTSA's car seat page, which also lists free car seat inspection by certified technicians. Check the label and the maker's instructions, and ask your pediatrician about your child.

Full specs

Britax Willow S
TypeInfant car seat
List price$279.99
Rear-facing weight4–30 lb
Rear-facing height17–32 in
Width16.9 in
Head rulewhen the top of child's head is at least 1 in (2.5 cm) below the top edge of head restraint
Base includedYes
Newborn insertInfant positioning pillow (optional): can be used with infants weighing less than 11 lbs (5 kg); harness inner loop/slot maximum 11 lbs (5 kg).
InstallationClickTight belt install of Alpine base (lap-shoulder belt), lap belt (with base), lower anchor attachments (with base), lap-shoulder belt (without base, American belt path), lap-shoulder belt (without base, European belt guide), lap belt (without base)
Load legNo
Anti-rebound barYes
RotatesNo
Works with strollersSelect Britax strollers (Britax compatibility chart: https://us.britax.com/support/instructional-videos-and-user-manuals/compatibility-charts)
Handle in the carThe carry handle must be adjusted to any locked position for use in a vehicle.
Aircraft labelCertified for aircraft, per the maker
No added flame retardantsYes
Expires after6 years

Compare the Willow S with

How each closest rival differs from the Willow S, from the makers' specs.

Ask the meadow

Willow S: questions answered

From Britax's published specs, last checked 2026-11-06.

Does the Britax Willow S rear-face longer than other infant seats?

24 of the 97 infant seats we track rear-face to a higher weight than its 30 lb. The highest is the Baby Jogger City GO 2 at 35 lb. NHTSA: stay rear-facing "until he or she reaches the top height or weight limit allowed by your car seat's manufacturer." (NHTSA)

Will the Britax Willow S fit three across or in a small car?

It's narrower than 66% of the infant seats we track, at 16.9 in. The narrowest is the Evenflo NurtureMax at 14.8 in. Fit depends on your vehicle; check each seat's manual and your vehicle manual. Car seat use and installation: see NHTSA's car seat page, which also lists free car seat inspection by certified technicians. Check the label and the maker's instructions, and ask your pediatrician about your child.

Can you use the Britax Willow S in a taxi or Uber without the base?

Yes. Britax lists a baseless install with the vehicle belt; see the manual for the belt routing.

Can you bring the Britax Willow S on a plane?

Yes, Britax lists it as certified for aircraft; look for the red-lettered label that says so. The FAA asks that a car seat go in a window seat so it doesn't block the aisle, and the crew will look for that label.

Willow S or SnugRide SnugLock LX: what's different?

By the makers' specs, the Willow S has an anti-rebound bar; the Willow S has no added flame retardants (maker's claim). See every spec side by side.

Is it OK to buy a used Willow S?

NHTSA publishes guidance on used car seats on its car seat page. Britax lists a lifespan of 6 years from manufacture for this model. Check the label and the maker's instructions, and ask your pediatrician about your child.

Still wondering? Write to us at hello@cribpicks.com and we'll look it up.

More infant car seats

Where these specs come from

Last checked 2026-11-06. Spot something wrong? Tell us. Read our editorial and safety policy and corrections.