Diono Radian 5 – A Toddler’s Point of View

R5 car seat review



Presenting to you our car seat review of the new car seat from Diono – the Radian 5. Or R5 as I like to just shorten it to.
In this review, I will be going through both rear and forward facing – though the seat is currently being used in the rear facing mode.
I do however always try to make sure I review the seats in all modes if possible.
NB! In the first photos the harness pads are fitted inside out by mistake – at the bottom of the post, you can see them fitted correctly.

The car seat was sent to us by Diono for an honest review. All thoughts and opinions are as always my own.

Quick Car Seat Info:

  • Extended Rear Facing Car Seat
  • Rear Facing from: Birth/25kg (55lbs)
  • Forward Facing from: 9 (20lbs)/25kg (55lbs) – with the top tether.
  • Re-Thread harness
  • Has the narrowest base
  • Full steel alloy frame
  • Memory foam padding inside seat
  • All round EPP energy absorbing foam
  • SuperGrip energy absorbing harness pads significantly reduce the impact of crash forces to the child
  • V3 Energy Reduction System provides ultimate protection in all collision situations – forward, rear, side impact or overturning
  • Aluminium reinforced sidewalls and headrest resist crash forces

Maximum height:

Forward-facing: The child is too tall for the car seat

• if the tops of the child’s ears are above the back of the car seat
• if the child’s shoulders touch the bottom of the headwings
• if the child is more than 144 cm tall
Rearward-facing: The child is too tall for the car seat if the top of the head is

  • less than 3.8 cm (1 inch) from the top of the car seat or if the child is more than 122 cm tall.

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First impressions…

Three R5s across in a VW Passat - you can see how much room is still left on the side of the base!
Three R5s across in a VW Passat – you can see how much room is still left on the side of the base!

The R5 is a very nice and narrow car seat. Using this seat it will be significantly easier to get 3-across in the back of the car than with many other car seats, but even though it’s narrow at the base – both my children who are almost 6 and 4 fitted very comfortably in the car seat – so don’t let its narrow base scare you.

51agjTiv19LDiono has made the recline of this car seat really good. It would have to be as it’s from birth – and even though the car seat comes with a default recline which changes depending on your front seats – there is an angle adjuster which you can also buy and use for older kids. I am currently using the adjuster, as without it – the seat was just too reclined for my 4-year-old.

He sleeps very well in it though and is very happy with his seat. The harness can be a little fiddly – I found it a little hard to tighten – especially to get that last one for the perfect snugness – but with a little bit back and forth it’s OK now. I do however hope that it is because the seat is so new – and not something that is meant to happen, because the harness is in its own category – hard to tighten during summer as the kids have only a thin t-shirt on. I hope it’s better come winter time and a thicker top will be used and that with day-to-day use it will soften up a bit.

The R5 has two different types of harness pads. One set for young/light children and one pair for when they have reached 15kg. The first set is quite small – just over the shoulder and is used from 0-15kg. Once the child hits 15kg it’s very important to change to the correct chest pads. The pads are a vital part of the car seat and must be used at all times. They are energy absorbent and significantly reduce the impact of crash forces on the child.

On the left are the larger pad that are used from 15kg and on the right is the small one that is used from birth up to 15kg.
On the left are the larger pad that is used from 15kg and on the right is the small one that is used from birth up to 15kg. (The larger pad is fitted the wrong side up!)

As Henry is 18kg he is using the larger pads in his seat. In some of my photos the pads are on the wrong way (note the instructions are on the outside instead of the inside)- which happened because my brain was firmly on holiday it would seem! But they have been changed back to the correct side hehe. So in the newer photos they are the right side up.




I find the R5 to be very simple to install. The instructions are easy to follow on the seat itself – and also in the instruction manual. I need to just point out though that I felt the instructions of where the locking clip goes should be more clear. I had to actually search for it in the manual and I think that if I wasn’t as clued up on car seats as I am, I would have gotten it wrong or possibly not used it at all because it wasn’t clear enough in the manual.

So just to clarify: The red locking clip goes over both the lap and shoulder belt on the side opposite of the female vehicle belt buckle. Which means next to the door if you are installing it on the sides to be even more clear on this. 

locking clip


The seat belt has only one route when rear facing and it’s quite a nice and wide space to get your hand and grab the buckle so I found that very simple.


The angle adjuster is here in use. Rear facing the seat also has a “foot” that clips on. This one is not used in forward facing mode.


Rear facing the seat uses a tether, but unlike other EU seats this one has only one. The top tether is both the RF tether and the FF top tether.

Make sure the tether is tightened until it shows green. You also might want to re-check it after installation and the child is in the seat. I found that it had turned red by then.


Like I mentioned before the seat is nice and narrow and I was able to get 3 across very easily.
Below is a few pictures that show this as well as how the good space to buckle up the boosters I had next to the seat.



The R5 bas is nice and narrow – look at all that space between the Monterey 2 and the base. (hence the base not showing up in the image hehe)


Henry showing off the seat in forward facing mode. Notice his legs? (Please note the chest pads are fitted the wrong side up)

When the seat is used in forward facing mode – it is vital that you put on the “safe stop”. It’s not hard to do and the instructions for it are simple to follow.


When the seat is used forward facing you also have a recline option on the base. Just remember that this is not to be used in rear facing mode.





Henry is very comfortable in the car seat. When it first arrived he actually fell asleep in it! haha

The memory foam is very nice and comfy – the seating is soft and unlike for example the Britax Two Way Elite – I find that this car seat’s bum area is much more padded.

Some people have been wondering about leg room in this car seat. As the car seat needs to rest on the front seat for support (because of no load leg) the installation doesn’t give options for increased leg room as the child grows. However I am quite comfortable saying that this won’t be an issue and that comfort certainly is not an issue.
Children are very flexible and will cross their legs Indian style, throw them to the side or simply just lean them up against the seat. There is absolutely no danger to the child’s legs in the event of an accident if they are doing this. There has in fact not been any recorded incidents where the child’s legs have been either broken or injured from simply being rear facing. So there is no need to worry!!

Comfy Feet &Happy Smiles


Notice the chest pads are on correctly here. With the grey on the inside along with the instructions facing in. :)
Notice the chest pads are on correctly here. With the grey on the inside along with the instructions facing in.





All in all we are really happy with this seat. Even though the R5 has a ‘re-thread’ harness I find it very simple to adjust to the correct height. There are however as I have mentioned before a bit of back and forth depending on child’s weight. I think that by always remembering to double-check once your child hits 15kg you should be fine because that’s when things start to change.

The instructions are all in all very easy to read but as I have also mentioned I do think they need a little bit of a re-work especially in regards to the locking clip.

Since we got the seat and to this review has gone live we have had a good chance to test the seat on longer journeys and as the below picture shows they are very comfy in their Diono seats.

The picture below was taken when we got home from a whole day at the Safari park, which is just over 2h drive away.

Caitiebelle is in her Diono Monterey 2 which we also wrote a review of and was given by Diono. So we are now a full Diono family!!

As you can also see – Henry uses the R5 in rear facing mode even though he is 4 years old now. There is no need to turn him until he has outgrown the car seat rear facing and he is so much safer in the rear facing position.

comfy in diono

Installation videos:



What do you think of the Diono Radian 5?  Has this review been helpful to you?