ISOFIX reduces some belt-routing errors, but it is not a click-and-forget guarantee. The child seat must be approved for the child and vehicle position, and any support leg or top tether must be used exactly as its manual states. Treat this guide as a preparation checklist; the manuals for the exact seat and rental car control the installation.
Confirm compatibility before collection
Ask the car-rental company for the vehicle model or class and the baby-equipment provider for the exact seat and base. A substituted car may have different rear-seat space, ISOFIX access, or floor storage. Review the seat manufacturer's vehicle list if one applies. Confirm how many ISOFIX positions exist when traveling with multiple children and whether luggage still fits.
Locate and connect correctly
Park safely, switch off the vehicle, and identify the lower anchor points using the vehicle manual or ISOFIX labels. Do not confuse them with other metal parts. Extend the seat connectors, align them without twisting, and push until the indicators show the state specified by the manufacturer. Pull firmly at the connection to check it has engaged, then complete any prescribed anti-rotation step.
Support leg or top tether
A support leg must rest where both manuals allow. Some vehicle floor compartments require an approved filler or prohibit leg placement; never guess. A top tether routes to a marked tether anchor, not a luggage hook or head restraint post. Remove only vehicle components the manual says may be removed. Do not combine ISOFIX and seat-belt installation unless the child-seat instructions explicitly require or permit it.
Fit the child and recheck
Set recline and head support for the child, remove bulky outerwear, and tighten the harness so it lies flat and snug according to the manual. Check that doors close without pressing the seat and the front seat does not brace it unless approved. Recheck indicators and harness after the first stop. If any step is unclear, ask a trained fitting service or provider rather than improvising.