| Mode | Weight | Height |
|---|---|---|
| Rear-facing infant | 4–30 lb | 17–32 in |
- Seat weight
- 8.99 lb
- Width
- Not published
- Usable life
- 6 years
- Aircraft
- Certified
1 / 8 Product image 1
Amazon product images. See this listing on Amazon
CERTAIN CONTENT THAT APPEARS ON THIS SITE COMES FROM AMAZON. THIS CONTENT IS PROVIDED ‘AS IS’ AND IS SUBJECT TO CHANGE OR REMOVAL AT ANY TIME.
Britax Willow S Infant Car Seat with Alpine Base
$279.99
Price on Amazon.com as of 2026-11-02 09:09 UTC, and subject to change.
An infant car seat with one mode: rear-facing infant 4 to 30 lb, 17 to 32 in.
At a glance
- Fits children from 4 to 30 lb
- Up to 32 in tall
- Rear-facing infant only
- Anti-rebound protection
- 16.9 in wide
- 6-year usable life
- Certified for aircraft use
Check the current price
Opens Amazon.com in a new tab. As an Amazon Associate I earn from qualifying purchases.
CERTAIN CONTENT THAT APPEARS ON THIS SITE COMES FROM AMAZON. THIS CONTENT IS PROVIDED ‘AS IS’ AND IS SUBJECT TO CHANGE OR REMOVAL AT ANY TIME.
Who is the Willow S Infant Car Seat with Alpine Base for?
The Britax Willow S is a rear-facing infant car seat sold with the Alpine base. Its manual allows babies from 4 to 30 lb and 17 to 32 inches, with the head at least 1 inch below the top of the head restraint. The base installs with LATCH or a belt, and the seat expires after 6 years.
Reasons to consider it
- An Alpine base that installs with LATCH, a lap-shoulder belt without locking the retractor, or a locked lap belt
- An extra belt path on the back of the carrier for installs without the base
- An infant positioning pillow for babies under 11 lb, on select models
- Aircraft certification when the carrier is installed without the base
Things to weigh up
- Britax does not publish the carrier weight on the product page
- The page lists height as less than 32 inches and says ranges may vary by model, so read the labels on the seat you buy
- Not certified for aircraft on the base
- The peek-a-boo canopy window comes on select fashions only
My take on the Willow S Infant Car Seat with Alpine Base
The Willow S suits parents who want the ClickTight Alpine base and a carrier that moves to select Britax strollers. Its manual gives the same limits, base installs and aircraft rules as the Willow SC manual. The differences are on the product pages: Britax does not publish a Willow S carrier weight and lists its height limit as less than 32 inches, while it lists the Willow SC carrier at 9.3 lb with an aluminum carry handle.
A research summary of Britax’s published specifications and manual, read . Not a hands-on test or a crash-safety rating.
Who the Willow S Infant Car Seat with Alpine Base fits
This seat covers one stage. Britax gives it a 6-year life from the date of manufacture, so check the date label before using a hand-me-down.
- Rear-facing infant4 to 30 lb · 17 to 32 in
- The child faces the back of the car, which keeps the head, neck and spine supported in a frontal crash. Keep this mode as long as the child fits it.
What are the Willow S Infant Car Seat with Alpine Base weight, height and age limits?
| Mode | Child weight | Child height | Minimum age | Conditions |
|---|---|---|---|---|
| Rear-facing infant | 4 to 30 lb | 17 to 32 in | Not published | Product page states height 'Less than 32 in'; 17 in minimum from manual |
A child must meet every limit for the mode they use. The labels on your seat and its manual are the final word.
Willow S Infant Car Seat with Alpine Base specifications
- Seat weight
- Not published
- Width
- 16.9 in
- Depth
- 28.1 in
- Height
- 24.11 in
- Usable life
- 6 years
- Aircraft use
- Certified for aircraft (see manual for which modes)
- Included base
- Alpine base
How the Willow S Infant Car Seat with Alpine Base installs
- Belt lock-off
- ClickTight installation (Alpine base). A lock-off clamps the vehicle belt so you do not have to switch the belt's retractor into its locked mode.
- Lower anchors
- Quick-push LATCH connectors. Check your vehicle manual for which seating positions have anchors, and switch to the seat belt once the child passes the anchor weight limit in the manual.
Every install is a fit between one seat and one vehicle. Read both manuals, and use a free inspection station if anything is unclear.
Will it fit your car?
At 16.9 in at its widest, this seat is one of the narrower ones in its class and is a candidate for three across in many mid-size cars.
- Check your vehicle manual for lower anchor positions and any head-restraint rules.
- Rear-facing seats need front-seat room: try the install behind the driver before you commit.
- Certified for aircraft use, so it can travel as a seat rather than checked baggage.
What features does the Willow S Infant Car Seat with Alpine Base have?
- ClickTight installation (Alpine base)
- Anti-rebound bar on base (ReboundReduce stability bar)
- ReboundReduce carry handle
- Quick-push LATCH connectors
- European belt path for baseless install
- Side impact tested to FMVSS 213a (per brand)
- UPF 50+ canopy
Colors listed in the US
Graphite Onyx, Jade Onyx, Glacier Onyx, Teak, Raven Black.
What to know before you live with it
Installing the Alpine base
The manual has you press the recline button, set the base against the vehicle seat back, and move it until the whole blue marker sits between the two lines on the recline indicators, with the car on level ground. Up to 4.7 inches of the base may hang over the seat edge. A lap-shoulder belt or the lower connector strap goes under the ClickTight and both belt guides before you close it. The ClickTight replaces locking a lap-shoulder belt retractor, but a lap belt must be locked. The base should move less than 1 inch at the belt path, and the indicator window must show only black.
Source: Britax Willow S with Alpine Base user guide P15000100 (PDF)
Without the base, and on a plane
The carrier can be installed with the vehicle belt alone. You secure the baby first, route the lap belt under the carrier's belt guides, and with a lap-shoulder belt you can take the shoulder part around the back through the European belt guide. The level line on the carrier must be level to the ground. The manual certifies the seat for aircraft only in this baseless form, using the aircraft lap belt through the baseless belt guides. It says the seat is not certified for aircraft on the base, because the aircraft belt is not compatible with the base.
Source: Britax Willow S with Alpine Base user guide P15000100 (PDF)
Harness fit and inserts
The harness ships in the inner loop, which is for babies up to 11 lb, and moves to the outer loop for 4 to 30 lb. The hip straps have an optional inner slot up to 11 lb and must not sit under the baby. Shoulder straps go in the closest slot below the shoulders, and changing slots means rethreading each strap from the yoke underneath. The buckle goes in the slot closest to, but not under, the baby. On select models there is a head pad and an infant positioning pillow, and the manual limits the pillow to infants under 11 lb.
Source: Britax Willow S with Alpine Base user guide P15000100 (PDF)
What the product page adds
Britax describes the cover and inserts as SafeWash fabric, safe to machine wash and dry and naturally flame-retardant with no added FR chemicals. The page lists the RightSize system, with adjustment points at the hips, shoulders and between the legs, and says the seat is side-impact tested according to FMVSS 213a. The canopy is UPF 50+ with a flip-down visor, and the peek-a-boo window is on select fashions only. The page also notes that weight and height ranges may vary by model because of regulatory changes, and tells you to follow the user guide and labels.
Source: Britax Willow S Infant Car Seat with Alpine Base product page
Is the Willow S Infant Car Seat with Alpine Base recalled?
No campaign in the current NHTSA child-restraint data names this model family, and I have not run a separate review for it. Check your seat’s model number and date of manufacture before use.
Willow S Infant Car Seat with Alpine Base: common questions
What are the Willow S weight and height limits?
The manual allows 4 to 30 lb and 17 to 32 inches, rear-facing only, with the top of the head at least 1 inch below the top edge of the head restraint. The product page lists the height as less than 32 inches.
Britax Willow S with Alpine Base user guide P15000100 (PDF) (opens in a new tab)
How much does the Willow S carrier weigh?
Britax does not list a carrier weight on the Willow S page. It lists the Willow SC carrier at 9.3 lb and its Alpine base at 10.2 lb, but those figures belong to the Willow SC listing.
Britax Willow SC Infant Car Seat with Alpine Base product page (opens in a new tab)
Can the Willow S go on an airplane?
Only without the base. The manual certifies the carrier for aircraft with a baseless lap-belt install and says it is not certified on the base, because the aircraft belt is not compatible with the base.
Britax Willow S with Alpine Base user guide P15000100 (PDF) (opens in a new tab)
When does the Willow S expire?
The manual says not to use the seat and base if they are older than six years or have been in a moderate or severe crash. The date is on the manufacture label on the carrier and the base.
Britax Willow S with Alpine Base user guide P15000100 (PDF) (opens in a new tab)
How is the Willow S different from the Cypress?
Britax lists the Cypress with 4 to 30 lb and 17 to 32 inch limits, a 9.7 lb carrier, double-knit mélange fabric and three padded inserts. Both pages list the Alpine base and the same outside dimensions.
Britax Cypress Infant Car Seat with Alpine Base product page (opens in a new tab)
Answers refer to the model and manual version on this page. Check the instructions supplied with your seat.
Before you buy
- Weigh and measure your child. The limits above are the manufacturer’s, and a child has to meet all of them for the mode they will use.
- Confirm the exact version. Colors, retail exclusives and model numbers change limits more often than you would expect; Britax lists 5 colors of this seat.
- Read the manual before you buy, not after. It is linked above and holds the fit rules, the install methods and the expiry.
- Check recalls by model number and date of manufacture, and register the seat with Britax so you hear about the next one.
Sources
Other Britax infant car seats
| Model | Top child weight | Seat weight | Width | Usable life |
|---|---|---|---|---|
| Willow S Infant Car Seat with Alpine Base (this seat) | 30 lb | — | 16.9 in | 6 years |
| Cypress Infant Car Seat with Alpine Base | 30 lb | 9.7 lb | 16.9 in | 6 years |
| Willow SC Infant Car Seat with Alpine Base | 30 lb | 9.3 lb | 16.9 in | 6 years |
| Arbor Infant Car Seat with StayTight Base | 30 lb | 9.9 lb | — | 6 years |
| Willow Infant Car Seat with Aspen Base | 30 lb | 8.99 lb | — | 6 years |
Seats to compare with the Willow S Infant Car Seat with Alpine Base
Other infant seats whose published weight and height limits overlap the Willow S Infant Car Seat with Alpine Base.
| Mode | Weight | Height |
|---|---|---|
| Rear-facing infant | 4–30 lb | 17–32 in |
- Seat weight
- 9.3 lb
- Width
- 16.9 in
- Usable life
- 6 years
- Aircraft
- Certified
$329.99Pindot Onyx · Amazon price as of 2026-11-02 09:09 UTC, subject to change
| Mode | Weight | Height |
|---|---|---|
| Rear-facing infant | 4–30 lb | 17–32 in |
- Seat weight
- 9.9 lb
- Width
- Not published
- Usable life
- 6 years
- Aircraft
- Certified
| Mode | Weight | Height |
|---|---|---|
| Rear-facing infant | 4–30 lb | 17–32 in |
- Seat weight
- 9.7 lb
- Width
- 16.9 in
- Usable life
- 6 years
- Aircraft
- Certified
34% off$249.99List price $379.99Ponte Glacier · Amazon price as of 2026-11-02 09:09 UTC, subject to change