Britax Marathon 70-G3 Convertible Car Seat – Top Reviews & Key Info

  • Britax Marathon 70-G3 Convertible Car SeatPrice Range: $250 to $290
  • GooGooLove: ♥♥♥♥ (4/5)
  • Pros:
    • Safecell Technology to absorb impact
    • EZ-Buckle System
    • Comfortable & plush
  • Cons:
    • Bulky
    • Shoulder pads don’t stay in place
    • Velcro patches that hold straps aside don’t really work
  • Child’s Weight & Length Limitations:
    • Rear-Facing:
      • Weight: 5-40 lbs
      • Height: 49″ or less
      • Seated Shoulder Height: 9″- 16.75″
    • Forward-Facing:
      • Weight:  Up to 70 lbs
      • Height: 49″ or less
      • Seated Shoulder Height: 12″- 16.75″
  • Product Weight & Dimensions: 19.5 lbs; 18.5″W x 26″H x 21″D

Most Helpful Reviews on the Britax Marathon 70-G3 Convertible Car Seat.

  • 5.0 out of 5 stars(5/5) – 8/1/2012 – We own a Britax Marathon 70 so I decided to put it next to the Marathon 70-G3 for a side by side comparison. For the most part the seats are practically identical with a few small differences. The harness adjustor strap’s release mechanism is the same, and I still find it awkward when compared to the Marathon and Roundabout 55 classic seats. Instead of pressing down, you need to press up. After nearly 11 years of dealing with seats that have easier releases, I still find this to be awkward. Harness height adjustment on this seat is a snap compared to the seats where you need to rethread the harness…. The seat also has the EZ-Buckle System which keeps the harness buckle in a forward position and keeps your child from sitting on the buckle. I can tell you that this feature is quite nice…. (read more and buy it at
  • 4.0 out of 5 stars(4/5) – 8/14/2012 – I have one each of the Britax Marathon and the Recaro ProRide for our two vehicles…. Pros of Both: -Sturdy, High Quality -Great padding -Plenty of adjustment for a good secure fit…. Cons of Both:… (read more and buy it at
  • 4.0 out of 5 stars(4/5) – 12/31/2012 – Britax is very easy to install in the car and easy to strap baby in. It’s nice material, feels sturdy, looks attractive. It is large. I think it works best in bigger cars or at least ones with more head space when rear facing (RF)…. (read more and buy it at
  • 4.0 out of 5 stars(4/5) – 8/25/2012 – Great carseat when ur child outgrows their infant seat. I did alot of research on ALL the convertible carseats on the market when my daughter was transitioning out of her infant seat and this one surpassed all the others in safety and quality…. One other BIG PLUS of this carseat is that it is easy to remove the cover to be MACHINE washed. Both my kids have had reflux problems so you know what I mean!  (read more and buy it at
  • We wish there were more helpful reviews out there! Do you have a review to submit? Please post it below!

Gear in Action

  • See a video by Britax here.

What the Makers Say

  • EZ-Buckle System retains the harness buckle in a forward position and prevents the child from sitting on the buckle when boarding
  • Base with 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
  • Tangle-Free, Five-Point Harness distributes crash forces across the strongest parts of the body and provides a secure fit
  • Harness Ultra Guard System (HUGS™) provides resistance to forward movement in the event of a crash…. (read more at

Any Safety Recalls :( ?

  • Not that we’ve heard.  For the most up-to-date infor­ma­tion, search the Con­sumer Prod­ucts Safety Division’s web­site here.


  1. Hay, It`s me. This is Tafser Ahmed . I read your article. i understand something on your article.Britax Marathon 70-g3 Convertible Car Seat is really very specially perfect for our so so cute kids. I purchased them several months ago. There are a plethora of reviews that pit the Britax against the Recaro, so to save you reading time, I’ll keep my review brief:

    Pros of Both:
    -Sturdy, High Quality
    -Great padding
    -Plenty of adjustment for a good secure fit (and our little girl is definitely behind the growth curve in weight: 1 year old and 17 pounds!)

    Thank you
    Tafser Ahmed

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