Joie bay latch SI plus
The Joie bay latch SI plus forward-faces up to 65 lb, is 19 in wide, and weighs 23.7 lb, per Joie.
- $269.99List price
- 65 lbHarness to
- 120 lbBooster to
- 23.7 lbSeat weight
bay latch SI plus: key facts
- The Joie bay latch SI plus forward-faces with a harness from 30 to 65 lb and 27 to 49 in tall; works as a booster from 40 to 120 lb and up to 60 in tall, per Joie.
- Outgrown by height: "Forward-Facing: The harness straps MUST be AT or JUST ABOVE the child's shoulders. For forward-facing harnessed mode, DO NOT use the headrest higher than indicated on the label on the child restraint (headrest position 11 as indicated under the backrest softgoods)."
- It installs with rigid lower anchors (LATCH) forward-facing + top tether (harness, child up to 40 lb), seat belt forward-facing + top tether (harness), rigid lower anchors + vehicle belt + top tether (harness, over 40 lb), high-back booster: lap/shoulder belt, rigid lower anchors optional or backless booster: lap/shoulder belt, rigid lower anchors optional.
- Joie says it expires 10 years after the date of manufacture.
- Joie lists it as certified for aircraft ("Forward-facing harnessed mode: This restraint is certified for aircraft use. Booster modes: This restraint is not certified for aircraft use, as aircraft belts will not accommodate proper installation of this child restraint. (manual warnings)").
- It's 19 in wide at the widest point and weighs 23.7 lb.
From Joie's manual and published specs. Always follow the limits on your seat's labels.
How the bay latch SI plus stacks up
Against the 22 harness-to-booster car seats we track. The shaded band is where the middle half of them fall; the dot is this one.
Within the typical range for harness-to-booster car seats (8 years to 10 years).
The same as most harness-to-booster car seats (65 lb).
Within the typical range for harness-to-booster car seats (18.3 in to 19.4 in).
Within the typical range for harness-to-booster car seats (16 lb to 25 lb).
Above the typical range for harness-to-booster car seats ($79.99 to $239.99).
What sets the bay latch SI plus apart
Measured against the 22 harness-to-booster car seats we compare, from each maker's published specs.
- Weight: 23.7 lbin the middle half of the 15 harness-to-booster car seats that publish it (16 lb to 25 lb)
Next to its closest matches
- Chicco MyFit Air ClearTex Harness + BoosterNext to it, the bay latch SI plus is 2 years longer before it expires; 1.5 in wider; 1.3 lb lighter.
- Chicco MyFit ClearTex Harness + BoosterNext to it, the bay latch SI plus is 2 years longer before it expires; 1.5 in wider; 1.3 lb lighter.
- Britax Grow with You Harness-to-BoosterNext to it, the bay latch SI plus is 1 years longer before it expires; 0.7 lb heavier; $30 more.
Flying with the bay latch SI plus
Joie's label: “Forward-facing harnessed mode: This restraint is certified for aircraft use. Booster modes: This restraint is not certified for aircraft use, as aircraft belts will not accommodate proper installation of this child restraint. (manual warnings)” It is 19 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 bay latch SI plus
Prices and availability change. We may earn a commission from some links.
- New for 2026. Some specs may not be published yet.
- 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
| Joie bay latch SI plus | |
|---|---|
| Type | Harness-to-booster |
| List price | $269.99 |
| Forward-facing weight | 30–65 lb |
| Forward-facing height | 27–49 in |
| Booster weight | 40–120 lb |
| Booster height | Up to 60 in |
| Seat weight | 23.7 lb |
| Width | 19 in |
| Head rule | Forward-Facing: The harness straps MUST be AT or JUST ABOVE the child's shoulders. For forward-facing harnessed mode, DO NOT use the headrest higher than indicated on the label on the child restraint (headrest position 11 as indicated under the backrest softgoods). |
| Installation | rigid lower anchors (LATCH) forward-facing + top tether (harness, child up to 40 lb), seat belt forward-facing + top tether (harness), rigid lower anchors + vehicle belt + top tether (harness, over 40 lb), high-back booster: lap/shoulder belt, rigid lower anchors optional, backless booster: lap/shoulder belt, rigid lower anchors optional |
| Load leg | No |
| Anti-rebound bar | No |
| Rotates | No |
| Aircraft label | Certified for aircraft, per the maker |
| Expires after | 10 years |
Compare the bay latch SI plus with
How each closest rival differs from the bay latch SI plus, from the makers' specs.
- ChiccoMyFit Air ClearTex Harness + Boosterforward-facing to 65 lb17.5 in wide$269.99
- 2 years shorter before it expires
- 1.5 in narrower
- 1.3 lb heavier
- ChiccoMyFit ClearTex Harness + Boosterforward-facing to 65 lb17.5 in wide$249.99
- 2 years shorter before it expires
- 1.5 in narrower
- 1.3 lb heavier
- BritaxGrow with You Harness-to-Boosterforward-facing to 65 lb23 lb$239.99
- 1 years shorter before it expires
- 0.7 lb lighter
- $30 less
- JoieBay Latch SI 3-in-1 Harness Boosterforward-facing to 65 lb19 in wide$239.99
- $30 less
bay latch SI plus: questions answered
From Joie's published specs, last checked 2026-11-06.
Will the Joie bay latch SI plus fit three across or in a small car?
It's wider than 64% of the harness-to-booster seats we track, at 19 in. The narrowest is the Chicco MyFit ClearTex Harness + Booster at 17.5 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 bring the Joie bay latch SI plus on a plane?
Yes, Joie 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. It weighs 23.7 lb to carry through the airport.
bay latch SI plus or MyFit Air ClearTex Harness + Booster: what's different?
By the makers' specs, the MyFit Air ClearTex Harness + Booster has no added flame retardants (maker's claim). See every spec side by side.
Is it OK to buy a used bay latch SI plus?
NHTSA publishes guidance on used car seats on its car seat page. Joie lists a lifespan of 10 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 harness-to-booster car seats
- ChiccoMyFitforward-facing to 65 lb17.5 in wide$239.99
- BritaxGrow with You ClickTight Harness-to-Boosterforward-facing to 65 lb25 lb$349.99
- Disney BabyMagicSquadforward-facing to 65 lb$179$179.99
- GracoTranzitionsforward-facing to 65 lb19 in wide$139.99
- EvenfloMaestro Sportforward-facing to 50 lb19 in wide$99.99
- Baby TrendHybrid SI 3-in-1forward-facing to 50 lb16 lb$99.99
Where these specs come from
- joiebaby.com/us/bay-latch-si-plus-harness-booster-with-footrest
- strolleria.com/products/joie-baby-bay-latch-si-plus
Last checked 2026-11-06. Spot something wrong? Tell us. Read our editorial and safety policy and corrections.