Diono Rainier Convertible + Booster Car Seat

We recently received the new Rainier Convertible + Booster Car Seat from Diono to review. The Rainier features extended rear-facing capabilities, it can comfortably seat rear-facing children from 2.3 – 22.7 kg (5 to 50 lbs) and forward-facing children from 10 – 29.5 kg (22-65 lbs) in 5-point harness mode. It also converts to a booster seat for children between 23 – 54 kg (50 – 120 lbs) or up to 144 cm (57″) in height.

The Rainier has new extra deep side walls that provide complete side impact protection. Its aluminum reinforced headrest has 12 height positions for adjustable head support and additional EPS foam surrounds the child’s head and body for extra side impact protection.

Diono Rainier Convertible + Booster Car Seat
Diono Rainier Convertible + Booster Car Seat

Main Features:

  • Full steel frame and aluminum reinforced sides for unmatched safety
  • Reinforced extra deep sidewalls lined with energy-absorbing foam give Rainier superior head and body protection
  • Comfortably seats rear-facing children from 2.3-22.7 kg (5-50 lbs), forward-facing children from 10 – 29.5 kg (22 – 65 lbs) and up to 144cm (57″) in a 5-point harness, then converts to a booster for children between 23 and 54 kg (50 – 120 lbs).
  • Unique SuperLATCH system that makes installation easy
  • Space saving design allows extra room for passengers while providing spacious interior for child
  • Folds flat for travel and is FAA certified
  • NCAP crash tested, the industry benchmark for verifying child seat performance in severe accident conditions
  • Infant body support cushions and memory foam for added comfort
  • Energy absorbing EPS foam and side impact protection provides added safety
  • Extra-long leg support for comfy road trips and multiple harness and buckle positions for custom fit
  • Safestop® energy-absorbing harness
  • Additional forward-facing recline position to accommodate different types of contoured vehicle seats, 12-position adjustable headrest, 5 shoulder and 3 buckle positions deliver a comfortable ride.
  • Rear-facing tether capability
  • UAS installation up to 29.5 kg (65 lb) child
  • Expandable sides and long seat bottom allow proper leg support
  • Sits low on vehicle seat for easy chd boarding and improved safety performance in a crash
  • Angled cup holder keeps a variety of drinks upright and within easy reach
  • Cover is machine washable and dryable
  • Rubber bottom grips for no-slip installation
  • Industry leading 12 year product life (from date of purchase)
  • Price: $379.99

Diono Rainier Convertible + Booster Car Seat


The Diono Rainier features a SuperLATCH™ system that makes the installation process very easy. Note that the SuperLATCH™ system is not supposed to be used with children over 35lbs (rear-facing) and 40lbs (forward-facing).  Also, if you want to use SuperLATCH™, both your car and the carseat have to be SuperLATCH™ compatible.

If you are not able to use SuperLATCH™ you will have to use your vehicle’s seat belt when installing, refer to the car seat’s instruction manual and your vehicle’s manual.

Unpacking of the car seat was pretty straightforward. I slid it out of the box and it was nicely packaged. The car seat comes folded up and you can easily unfold it by following the simple instructions. Our 4-year-old son is just under 40lbs so we are still using SuperLATCH™ but I also I installed the seat using my vehicle’s seat belt to try it out. It took a bit more time to figure out than using SuperLATCH™ but I got it done within a few minutes. We have it front-facing for our eldest but it can also be used rear-facing for up to 50lbs, one of the highest rear-facing weight limits on any car seats on the market.

Something important to note is that the back of this car seat is quite long so in a rear facing position, it needs a lot of extra room. If you do have a small car be sure to look at your measurements carefully before purchasing. You can also invest on their angle adjuster to get a bit more of extra space.

Diono Rainier Convertible + Booster Car Seat

Super LATCH installation


Diono Rainier Convertible + Booster Car Seat

Seat Belt Installation


Diono Rainier Convertible + Booster Car Seat

Tether Installed



The Rainier features a 5-point-harness, 12-position adjustable headrest, 5 shoulder and 3 buckle positions to deliver a comfortable ride. The harness height can be adjusted at the back of the seat and you can easily adjust the harness at or below the shoulders for rear-facing children and above for forward-facing.

The crotch strap and width of the seating area can also be adjusted depending on the size of your child.


This car seat has a full steel frame and aluminum reinforced sides, it features EPS energy-absorbing foam and a Safe-Stop energy-absorbing harness. It has also been NCAP crash tested, the industry benchmark for verifying child seat performance in severe accident conditions.

The steel framework makes this a very strong car seat and all the most important components and side impact are constructed of steel. It is comforting to know that your child will be as protected as possible while properly strapped in this car seat.

Note that all that steel does add weight so consider this if you are looking for a car seat that you can easily take out and exchange between cars or a carseat that you plan to take on plane rides, even though it is FAA certified and it does folds flat this is a pretty heavy car seat!

Covers and Padding:

The entire seat covering and body insert is removeable and machine washable but only in a front loading machine. You can also purchase new covers if needed and there’s a variety of fabrics and colours available.

Other Features:

The Diono Rainier is also one of the slimmest and least-bulky car seats available on the market. It means that you can actually fit three of these across the backseats of most vehicles. Not bad for big families.

In general we have really enjoyed testing out the  Rainier Convertible + Booster Car Seat. It is a smart investment because your child can use it from 5lbs up to 120lbs and it has pretty high safety  ratings. It also allows you to keep your child rear-facing up to 50lbs.

Diono Rainier Convertible + Booster Car Seat

Diono also offers some wonderful accessories that are a must have for your vehicle when you have little ones. We received the Easy View Plus™ mirror and their Stuff ‘n Scuff™ washable car seat organizer and we love them both. I use their mirror for my 1 year old who is still rear-facing and I really like how unique it is, it doesn’t block visibility like other larger mirrors do and it has a unique light and remote to check baby in the dark! The car seat organizer has also being wonderful, it protects the back of the seat from muddy, dirty shoes, a must have during the winter time.

Diono Rainier Convertible + Booster Car Seat

Diono Rainier Convertible + Booster Car Seat

Disclosure: I received a sample of a product to facilitate this post. All views and opinions stated on this post are 100% my own.