Compact, safe booster with ISOFIX — but not the cheapest buy

The Maxi-Cosi Tanza i-Size is worth buying if you want a foldable, ISOFIX high-back booster with strong safety credentials, but at £79.99 it is not the best-value option in this category right now. Its 4.4/5 rating from 3,157 reviews, plus 400+ bought last month, shows broad appeal, while the current price matching its RRP makes it easy to justify only if the folding design and Maxi-Cosi name matter to you.

First impressions: practical, compact and easy to live with

At 5.32kg and measuring 59.5cm x 28cm x 45cm when folded, the Tanza i-Size is clearly designed for families who need flexibility. That compact fold is the standout feature here: it makes storage simpler and should suit households that switch cars, need to tuck the seat away between uses, or want a booster that is less awkward to move than a fixed high-back seat. The full black finish is understated and easy to match with most interiors.

What does the Tanza i-Size actually offer?

This is a Group 2/3 forward-facing seat for children from 100–150cm, roughly 3.5 to 12 years old. Maxi-Cosi says it is built to i-Size ECE R129 standards and uses ISOFIX attachments, which is a meaningful plus for UK buyers because it gives a more secure installation than a seat relying only on the adult belt. The 10 headrest positions are another useful detail: growing children do not all fit the same way, and a broader adjustment range should help the seat last through several years of use.

The G-CELL Side Impact Protection is the other major safety talking point. According to Maxi-Cosi, it is designed to spread side-impact forces away from the child, which is the kind of protection parents want in a high-back booster used for school runs, motorway trips and stop-start UK traffic alike. The padded seat and elevated seating position should also make it more comfortable for longer journeys and improve outward visibility for younger passengers.

How does it perform in real-world use?

On paper, the Tanza i-Size is well judged for daily family life. The foldable design should be especially handy for grandparents, childminders or families with limited boot space, and the 5.32kg weight keeps it manageable. The seat’s adjustability is a real strength too: 10 headrest positions suggest it can adapt better than simpler boosters that outgrow quickly.

The main trade-off is value. At £79.99, it sits above the average tracked price of £75.96 and currently has no discount from its RRP. That matters because there are cheaper alternatives with stronger ratings: the Graco Junior Maxi i-Size R129 Highback Booster is listed at £40.00 with a 4.7★ rating, while another Graco version is £34.99 with the same 4.7★ score. Even the CBX by CYBEX Solution XI-Fix is £71.99 and rated 4.7★. So while the Maxi-Cosi is well specified, it is not the cheapest or highest-rated option in the shortlist.

Build quality and long-term ownership

Maxi-Cosi’s use of Eco Care fabrics made from 20 recycled plastic bottles, without hazardous chemicals, adds a welcome sustainability angle. That will matter to buyers who want a child seat with a cleaner materials story, though it does not change the core buying decision as much as safety, fit and price.

The biggest strength here is the combination of foldability, ISOFIX and i-Size compliance. The biggest weakness is that the current price is also the highest recorded price in the supplied data, which makes this a poor moment to buy if you are purely chasing value.

How does it compare with alternatives?

Against the Graco Junior Maxi i-Size R129 models, the Maxi-Cosi offers a more premium-feeling feature set with folding convenience and ISOFIX, but it costs roughly £40-£45 more. Against the CBX by CYBEX Solution XI-Fix at £71.99, the Tanza is still pricier while not clearly outperforming it on the data provided. If your priority is the lowest cost per year of use, the Graco seats look stronger. If you want a more portable booster with a compact fold, the Tanza has a clearer reason to exist.

Final take

The Maxi-Cosi Tanza i-Size makes sense for families who value portability, ISOFIX security and a seat that can be folded away between uses. If you mainly want the best price or the highest user rating, there are cheaper and better-rated rivals to consider first.