Help with car seat for 3 yr old please!

ByAmusedLurker · 2026-01-04T15:39:42+00:00

DD turned 3 at the start of October and we’d like to move her up to the next size car seat ahead of no. 2 coming later this year. She’s 16kg and 100cm but we’d feel more comfortable keeping her in a five point harness for a bit longer rather than going straight to a HBB. She’s currently in a maxi-cosi mica and we’ve been looking at the maxi-cosi onyx or titan as we’re reasonably happy with the brand. Can’t really tell the difference between the two though and not sure if we should also look at Britax or Joie options? TIA!

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Turmerictea · 04/01/2026 15:40

Not sure myself! Dd is same age and size, we have a Joie and Im not sure whether to level up!

Original poster

ByAmusedLurker · 04/01/2026 15:50

Turmerictea · 04/01/2026 15:40

Not sure myself! Dd is same age and size, we have a Joie and Im not sure whether to level up!

It’s such a minefield! Thought we might as well take advantage of the Jan sales though. Had a look in JL and liked the onyx but they didn’t have a huge range so immediately confused as soon as I looked online at home.

OP posts:

BertieBotts · 05/01/2026 00:38

Yes the Onyx and Titan are both good options. Britax Advansafix/Evolvafix as well. These have all had good results in crash testing and can use the harness up to 105cm/18kg (22kg with the Britax seats).

Silver Cross Balance i-size is good as well, this is also 21kg weight limit.

Joie have a couple of interesting ones - i-Irvana Max which has a 25kg/125cm limit on the harness, though I think this might not be necessary for you unless she is only just 3 or you're worried the 105cm won't be enough height. And i-Plenti which is one of the 105cm/21kg type but the belt positioning for the high back booster mode looks very good. However, Joie have previously not had very good performance for their forward facing harness seats, and they haven't had any newer seats tested which have broken this trend, so I'd preferably lean towards the brands with a more solid FF harness safety reputation.

@Turmerictea if you don't need the seat for another child, then keep LO in it until outgrown. It is better to wait until they are fully ready for a high back booster than to buy a seat which covers both classes, if you can hold off then do. If you do want to move up for whatever reason, the above seats are the FF options I would look at. There are also rear facing options lasting up to 125cm and then 21~36kg, though you'd have to buy a high back booster after this unless you go for Avionaut Stardust or Tinyseats 2.

Original poster

ByAmusedLurker · 05/01/2026 09:48

BertieBotts · 05/01/2026 00:38

Yes the Onyx and Titan are both good options. Britax Advansafix/Evolvafix as well. These have all had good results in crash testing and can use the harness up to 105cm/18kg (22kg with the Britax seats).

Silver Cross Balance i-size is good as well, this is also 21kg weight limit.

Joie have a couple of interesting ones - i-Irvana Max which has a 25kg/125cm limit on the harness, though I think this might not be necessary for you unless she is only just 3 or you're worried the 105cm won't be enough height. And i-Plenti which is one of the 105cm/21kg type but the belt positioning for the high back booster mode looks very good. However, Joie have previously not had very good performance for their forward facing harness seats, and they haven't had any newer seats tested which have broken this trend, so I'd preferably lean towards the brands with a more solid FF harness safety reputation.

@Turmerictea if you don't need the seat for another child, then keep LO in it until outgrown. It is better to wait until they are fully ready for a high back booster than to buy a seat which covers both classes, if you can hold off then do. If you do want to move up for whatever reason, the above seats are the FF options I would look at. There are also rear facing options lasting up to 125cm and then 21~36kg, though you'd have to buy a high back booster after this unless you go for Avionaut Stardust or Tinyseats 2.

Edited

Thank you so much for such a helpful and detailed response!

Is there a significant difference between maxi cosi and britax and the different seats? She is only 3 and 3 months so maybe the higher weight limit for the harness would be better, unless she reaches the height limit first I guess.

thank you!

OP posts:

BertieBotts · 05/01/2026 14:44

If she follows along the same line she's currently on, bearing in mind children tend to grow more in spurts than a consistent line, and it's winter so she might gain weight more slowly over the summer, she will probably reach 18kg and 105cm around about her fourth birthday. The line for weight is showing just past, whereas the one for height splits around that age so it could be before or after depending on which set of data the chart is using.

It's not the end of the world to go over a tiny bit on the height if the weight is OK, so the Britax or Silver Cross seats might be worth it on that count, or the Joie i-Irvana Max if you are really sure you want to keep her in a 5-point longer. The Britax seats have a sort of hook which is used in high back booster mode to support and hold the seatbelt between the legs which can feel like a bit of a compromise if worried about moving out of a 5 point harness.

Other than this though no, there's not much difference in terms of build quality and safety ratings, they are all good. You might be able to look at them in store to see which you prefer and which shape of seat seems to suit her build best. The Britax are quite wide and open at the base, which means that children who are very slim can sometimes seem to have a bit too much space here.