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Diono Rainier All In One Booster Car Seat Review

Editor rating


User's rating

48 reviews


Excellent weight range in both modes

Extended weight range in rear facing


12 position headrest


Lengthy installation


Narrow belt path


If you are on a budget and want to buy the best booster seat for your toddler, then this is a good option for you under $300. You can fit 2 across the car seat if you have more than 1 kids.

Introduction to brand and model

The Diono Rainier All in one comes from a brand which is known for its excellent safety ratings. Diono is based in the US and is known for manufacturing excellent child safety seats. This is one of the best selling booster car seats as it comes with weight booster of 120 pounds according to the manufacturer.The list of best convertible car seats 2019 is also available at bestbabyessentials.  Let us see what Diono has to offer and if this is an ideal choice for you and your baby.

Best Booster All In One Car Seat

The Diono Rainier All in one is a booster car seat which means that it will stay with your child for longer period. The seat is one of the few seats which offer an exceptional weight range in the rear facing mode. If your child grows above the weight range, this top rated booster car seat will provide you a boost of 120 pounds so you can put it to longer use.

Key features

The most notable feature of Diono rainier is its upper limit weight range with and without the booster. The weight limit in both the rear and forward facing mode is exceptional. It comes with a machine washable cover so it is very easy to wash it if your baby makes a mess. It is a low profile seat which allows for the convenience of putting the seat in and out of the car. It can be folded flat; therefore, it is easy to carry it anywhere. So you can say that it is the top rated portable car seat of 2019. The aluminum side walls and the steel frame ensure adequate safety for your child.

Other features:

  • Cup holder
  • Rear facing top tether
  • 10 year life span

Usage According to Height and Weight of Baby

Multiple configuration usage

The Dion rainier works in a dual positioning mode. It also provides a booster of 120 pounds.

Rear facing

The rear facing mode is probably the most attractive thing about this seat. It can provide a weight range of 5 – 50 pounds in the rear facing mode, which is an exceptional upper limit weight range.

Forward facing

The forward facing mode isn’t bad either. It can accommodate from 20 – 90 pounds in forward-facing mode. The 90 pounds weight range is an ideal weight range which ensures that you can use it for longer without even having the need to use the booster.

Booster mode

Dion rainier is one of the best quality booster car seats. It offers a booster position which you can put to use when your child exceeds the rear facing limit. This is an ideal booster car seat for parents who want a budget car seat with good features.

Diono Rainier ALL IN ONE installation

The Super Latch system works just fine and you can hear a click sound when it is properly fastened. It also has an indicator to show if it is locked or not. The rest of the installation is however not so easy.

First, the seat is heavy and the rear facing belt path is too narrow for both seat belt and latch. There are many steps you need to follow before installation. Furthermore, the crotch strap is difficult to remove.

Diono Rainier ALL IN ONE Design and Specifications

The seat weighs about 29.79 pounds. The design is narrow and the sides are not adequately padded as well. So if you are planning to go for a long ride, your child may feel uncomfortable.

The harness position is for heights from 8 to 16.5 inches. The recommended height range is from 57 “ in forward-facing and 44 “ in rear facing.


The Rainier measures a width of a maximum of 18.5 inches, a depth of 9.5 “ and a height of 24.5 inches.

Safest Booster Car Seat

The Diono Rainier comes equipped with adequate safety features. It has aluminum reinforced sidewalls which are lined with the EPS foam to absorb the outer impact forces. Plus the steel frame ensures side impact protection. It is one of the safest booster car seats you can buy in this price.

Safety Problems you may face for newborns

So far you can be sure that this seat is safe for your baby. There is nothing in this seat that we found to be unsafe as it is quite well built for safety. However the inner shell is not that padded as it should be. It might be. In case of an impact, your child may experience some nudge or budges.

Best Booster Car Seat under 300$

The Rainier has proved to be the best baby car seat under $300. It is for parents who want a booster car seat in a budget. It comes with some pretty nice features and you will not regret buying it.

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