Car hire with a child seat in the Algarve: rent one or bring your own?

The decision usually happens at the baggage carousel: haul your own seat along, or take the rental company’s? Both have good arguments. What is not up for debate is the law — in Portugal it is unambiguous, and it is enforced.

What Portuguese law requires

The Código da Estrada requires a suitable restraint for children up to 135 cm tall or under 12 years old. Whichever comes first applies: a tall ten-year-old over 135 cm may use the normal belt; a small eleven-year-old may not.

The rule covers every vehicle — private cars, rentals and taxis alike.

Children under 12 may not sit in front. The one exception that matters in practice concerns babies: a rear-facing seat in the passenger seat is allowed if the airbag is demonstrably switched off. In many small hire cars it cannot be switched off — which settles the question.

Police may collect the fine on the spot. The amounts run into three figures and bear no relation to what a seat costs.

Which seat for which child

Portugal follows the European standards. Seats approved to ECE R44/04 or the newer i-Size (R129) are accepted:

• Infant carrier, roughly 0–13 kg — rear-facing, on the back seat
• Child seat, roughly 9–18 kg — forward-facing, on the back seat
• Booster, roughly 15–36 kg — until the normal belt sits properly across shoulder and hips

The weights are guidance, not hard borders: what matters is that child and seat fit each other and that the belt runs correctly.

Renting one: what goes wrong

Almost every supplier lets you add a seat, usually at the last booking step. Three things worth knowing first:

A booking is a request, not a promise. Very few companies guarantee a specific seat. In high season it happens that only a booster is left at the desk although an infant carrier was booked. Arriving early in the day improves your odds.

The group has to match. The booking form asks for age, but size and weight are what count. Give both; call if in doubt.

You fit it yourself. For liability reasons most companies will not install the seat. Budget ten minutes in the car park with tired children beside you. And check whether the car has ISOFIX at all — in the small-car classes that is not a given.

The daily fee adds up. Over two weeks it easily reaches the price of a new seat.

Bringing your own: what speaks for it

Most airlines carry child seats in addition to the baggage allowance at no extra charge — get that confirmed in writing beforehand, as the rules differ. Then the familiar seat travels with you: the one your child already sleeps in, and the one you know has not been sitting in a garage for eight years.

The price is physical: a bulky object through two airports. Manageable with one child, a job with two and luggage.

The honest rule of thumb: up to about a week, renting is more comfortable. From two weeks, with a child under two, or if you are bringing a travel buggy anyway, your own seat wins.

The airport transfer

One point many people miss: taxis in Portugal are not obliged to carry child seats. If you have an hour’s drive to the hotel after landing and only collect the hire car the next day, sort that out in advance — or pick the car up at the airport straight away.

What to check when comparing

When you compare car hire for the Algarve, three lines matter more than the daily rate: whether a child seat can be booked at all, whether the fee is capped, and whether the car has ISOFIX.

Compare car hire prices for the Algarve

If you are travelling with small children anyway, it is worth reading Benagil with a toddler and Minimum age for boat tours first — the rules on the water are entirely different from those in the car. What the rental insurance actually covers is in Car hire excess.

As of September 2026. This page reports the rules but is not legal advice. The Código da Estrada and your supplier’s terms are what bind.