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Review of Britax Marathon 70-G3 Convertible Car Seat
4.70 stars Excellent Form 428 Reviews
Reviewed on: June 13, 2013 Author:
Price Range

$212.77 - $289.99

Where to Buy
Pros & Cons


  • Very safe and sturdy with integrated steel bars and side impact protection
  • 5-point harness with a holder that makes boarding quick and easy
  • Deep comfortable car seat with recline
  • Easy to install and remove with push button release and built-in-lock-offs
  • Two-position buckle and a no re-thread harness
  • Stylish looking and easy to clean fabric
  • Great quality and value for money


  • Little heavy
  • Not recommended for taller babies
Review Summary

This is the summary of consumer reviews for Britax Marathon 70-G3 Convertible Car Seat. The BoolPool rating for this product is Excellent, with 4.70 stars, and the price range is $212.77 - $289.99.

The Britax Marathon 70-G3 convertible car seat is a rear and forward facing recline, designed with various high-end revolutionary safety features for child’s comfort and positioning. It comes with a Safecell Technology Base which is designed to compress in 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. A side impact protection system 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.

The Britax Marathon 70-G3 can transport children from 5-40 pounds in rear facing position and 20-70 pounds in forward facing position. The 5-point harness is tangle free with an EZ-buckle system to retain the harness buckle in a forward position to prevent the child from sitting on the buckle when boarding. The harness holders keep the traps pulled to the sides to make boarding quick and hassle-free. The Energy-Absorbing Versa Tether has a two-point attachment to minimize forward rotation while anchoring the top of the child seat. Other great features include a no-rethread harness and an easy-remove cover that allows access to belt paths from front. The two buckle position provides a snug and secure fit. The recline positions, comfort pads, and infant body pillow provide premium comfort and positioning.

Some reviewers mention that this seat is bit heavy and also not suitable for taller babies. It does not come with an infant position insert and at times tightening the straps in rear position could be difficult.

Overall, the Britax Marathon 70-G3 convertible care seat combines safety, comfort & ease for the ultimate value in child safety. Compact and plush design makes it a desirable companion even for aircraft travel.


  • Weight: 19.5 lbs
  • Dimensions: 18.5W x 26H x 21D inches
  • Seating Compartment Height: 23.5 inches
  • Seat Area Depth / Width: 11 / 11 inches
  • Shoulder Width: 13 inches
  • Harness Slot Heights: 8.5 / 9.5 / 10.5 / 11.5 / 12.5 / 13.5 / 14.5 / 15.5 / 16.5 / 17.5 inches
  • Buckle Strap Depths:  5 / 7.5 inches
User Voice
Britax Marathon 70-G3 Convertible Car Seat
Easy and secure installation using Latch system Sturdy Comfortable Soft and high quality material Easy to clean
Review Group #: 1 Rating :
5.00 stars
23 Reviews See Details
Latch system works perfectly Easy to buckle Height adjustable shoulder straps Can be used as front facing or rear facing car seat
Review Group #: 2 Rating :
5.00 stars
9 Reviews See Details
Crotch strap holder leans forward making it easy to use Height adjustable harness straps Tightening the straps can be little difficult in rear-facing position
Review Group #: 3 Rating :
4.50 stars
15 Reviews See Details
Deep seat for comfort Fits easily in any car Loved and recommended by users
Review Group #: 4 Rating :
5.00 stars
10 Reviews See Details
More comfortable than some other smaller seats Not recommended for tall babies Worth the money
Review Group #: 5 Rating :
4.50 stars
12 Reviews See Details
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Review Sources
Britax Marathon 70-G3 Convertible Car Seat
Britax Marathon 70-G3 Convertible Car Seat, Onyx


Rating : 4.70 stars Form 428 Reviews
Ratings Badge
Rating : 4.70Excellent
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