Review - Britax MARATHON 70 Car Seat in Onyx ~ The Ultimate in Safety, Style and Comfort

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BritaxPicking out a car seat was one of the most intimidating tasks I completed as a soon-to-be parent.  I can remember how daunting it was knowing that your brand new bundle of joy would be protected by the piece of equipment you selected and how you weren't allowed to leave the hospital with your baby without first having a car seat properly installed.

Once Riley outgrew her rear-facing car seat, we received a hand-me-down from a friend, but it didn't seem very comfortable and it definitely wasn't convenient or well-designed.  Britax, a leader in quality mobile safety products for over 70 years, allowed Riley and I to review the MARATHON 70 Car Seat in Onyx.  Keep reading to learn more!

I reviewed the MARATHON 70 Car Seat in Onyx from Britax, which retails for $289.99, but is currently on sale for $230.99 with FREE SHIPPING.

Britax Marathon 70 Car Seat

The Britax MARATHON 70 Car Seat in Onyx is a plush, well-designed car seat that looks to be the epitome of comfort, style and safety.  This car seat can be used as both a rear facing and forward facing safety device, making it extremely versatile and able to be used from birth until your child reaches 49 inches in height or 70 pounds in weight.

The first thing I needed to do in order to configure the MARATHON 70 for my 2.5 year old toddler, was to change the length of the five point harness as well as the position of the buckle.  This was extremely quick and easy and was completed in minutes.  Next, I was able to adjust the harness height in a matter of seconds, thanks to the quick-adjust harness.  Once these steps were done and I removed the infant body pillow, it was time to install the MARATHON 70 in our family vehicle.  Check out the video below to see just how quick and easy it was!


As you can see, using the Latch Method of installation was so simple and fast, that I was amazed!  The Energy-Absorbing Versa-Tether and premium lower latch connectors were two features that our last car seat lacked, but now I feel so much more at ease knowing that the Britax MARATHON 70 is so securely attached to our truck's frame.  If you need to use the seat belt installation method instead, rest assured that Britax has equipped this car seat with built-in lock-offs which hold the seat belt tautly in place, allowing you a secure fit.

Britax Marathon 70 Car Seat in Onyx Britax Marathon 70 Car Seat in Onyx
Britax Marathon 70 Car Seat in Onyx
Britax Marathon 70 Car Seat in Onyx

Britax even thought to include the installation instructions on the side of this car seat too!


Although installation was a breeze, I wouldn't be doing my duty if I didn't let you know all of the MANY safety features of the MARATHON 70 car seat.  Now, I have complete peace of mind knowing my precious little girl is traveling in one of the safest car seats I've ever seen!Britax Marathon 70 Car Seat in Onyx

  • SafeCell™ Technology features SafeCells designed to compress in a crash, significantly lowering the center of gravity and counteracting the forward rotation of the child seat which normally propels the child toward the front seat.
  • Integrated Steel Bars strengthen the connection to the vehicle and reduce forward flexing of the child seat during a crash.
  • Energy-Absorbing Versa-Tether® features a staged-release tether webbing to slow the forward movement, reducing the crash forces reaching the child, and a two-point attachment to minimize forward rotation while anchoring the top of the child seat.
  • Side Impact Protection comprised of deep side walls lined with energy-absorbing EPP foam distributes crash forces, shields from vehicle intrusion, and contains the head, neck and body.
  • Harness Ultra Guard System (HUGS™) provides resistance to forward movement in the event of a crash.
  • Tangle-Free, Five-Point Harness distributes crash forces across the strongest parts of the body and provides a secure fit.
  • Quick-Adjust, No-Rethread Harness repositions the harness shoulder height without disassembling the harness straps.
Britax Marathon 70 Car Seat in Onyx

All Installed and Ready to Take for a Spin!

Britax Marathon 70 Car Seat in Onyx

Riley Gives the Britax MARATHON 70 Car Seat TWO THUMBS UP!


Riley thought that her new Britax MARATHON 70 car seat was much more comfortable than our previous model.  I'm sure this was because of the high-density comfort foam layer as well as the padded buckle protector included.  A few times, we've accidentally pinched Riley's inner thigh while fastening the safety buckle, but now the padded protector will ensure this no longer happens and the buckle won't have the opportunity to rub uncomfortably against Riley's legs either.

She also commented on how smooth the MARATHON 70's Easy-Remove Cover was.  I'm happy knowing that should Riley have a spill or get it dirty somehow, the cover will easily come off of the car seat without having to uninstall the entire seat from the vehicle.  Now I can toss the cover in the washer and it will be good as new again!

I couldn't be happier with the new Britax MARATHON 70 car seat, for it is the hallmark of classic design, safety and style, all rolled into one!  If you are in the market for an extremely versatile car seat, which could easily be used for many years, then don't hesitate to purchase the Britax MARATHON 70.



Product-Review-5 Stars PNG8
Disclosure:  I received the MARATHON 70 Car Seat in Onyx from Britax in order to facilitate my review. No other compensation was received. This product review is based on my own personal experiences with this item and is completely honest and objective.
I'm a former 7th grade Science teacher turned stay-at-home mom that lives in Houston, Texas. I am married to my college sweetheart and have a beautiful daughter named Riley, who definitely keeps me on my toes! I am also involved in starting a small business which would both manufacture and sell an invention that I've patented, called Toothpaste 2 Go. I love interacting with my readers and hope to learn as much about you as you learn about me!

Melissa @ Mommy Living the Life of Riley!
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