See All Convertible Car Seats

Britax Marathon Classic

*Est. $200
August 2012
by ConsumerSearch
Britax Marathon Classic

  • High crash ratings
  • Side impact protection
  • No-twist straps
  • High weight limit
  • High weight limitHarness must be manually rethreaded
  • Big and bulky
Where to Buy

The Britax Marathon Classic (*Est. $200) formerly known as the Britax Marathon, is a long-time favorite of parents and reviewers alike. .The only complaints the Marathon Classic has garnered over years of use are about its bulkier size and weight.

A safe seat that will last for years

The Marathon Classic gets consistently high crash test ratings. Among its chief safety features are deep, rigid sides with energy-absorbing foam side impact protection, and softer, high-density foam for comfort throughout the chassis. Unlike other car seats, the Marathon Classic's energy-absorbing tether stabilizes the car seat from the top in both the forward and the rear-facing positions, dramatically reducing the motion of the car seat and thus reducing the impact of a crash on the child. Finally, the Marathon Classic's thick and sturdy five-point harness is equipped with pads that keep the top restraint of the harness in place over the child's chest, ensuring that the harness provides maximum restraint.

Easy to install

Described by one reviewer as "a dream to install" compared to other car seats, the Marathon Classic has push-button, seatbelt-style attachments that you can connect from above to the car's anchors without digging in between the seats. The Marathon Classic is also equipped with lock off fasteners that keep the seat belt tight around the seat when LATCH connectors are used. A tether secures the seat from the top in both forward and rear-facing positions for stability. The Marathon Classic has thick, nontangling harness straps that are easy to adjust lengthwise from the seat front. However, the harness must be rethreaded to adjust the Classic's height -- and you have to take the seat out of the car to do this.

Comfort that continues into adolescence

 With a 65-pound weight rating and a maximum height of 49 inches, the Marathon Classic allows parents to keep children in a five-point harness longer, which means it's likely the only car seat your child will ever need. The Marathon Classic's chassis is lined with high-quality foam that provides energy absorption in a crash and softer cushioning. It offers rear and forward-facing recline positions to keep kids comfortable, and the protective side wings provide a comfortable point for sleeping. An attachable cup holder and a travel cart for airport use can be purchased separately. Because of its size, this may not be the best choice for smaller vehicles or families who need to install three seats in a row.

User manual not easily downloaded

No complaints about Britax service were found in our research of the Marathon Classic. The Britax website offers comprehensive installation instructions for all car seat models, but you have to have the date of manufacture available. All Britax car seats carry a one year warranty against defects in materials and workmanship with proof of purchase. Like most car seats, the seat expires and should not be used after seven years.

The bottom line

The Marathon Classic offers the high weight rating and the comfort and safety features that made it one of the most highly rated convertible car seats, but it is bulkier and heavier than some other models. It falls in the lower end of the price range for quality car seats, and it should last as long as your child needs a car seat.

Where To Buy
Britax Marathon 70-G3 Convertible Car Seat, Onyx

 (5 reviews)
Buy new: $289.99 $284.50   11 Used & new from $224.00

In Stock. Eligible for FREE Super Saver Shipping


Our Sources

1. crash-tests the Britax Marathon for its car seat roundup. Ease of use and fit to vehicle are also evaluated. To read the full test results, you must be a subscriber.

Review: Convertible Car Seats, Editors of, May 2012

2. National Highway Traffic Safety Administration

The Britax Marathon earns 3 stars out of 5 for overall ease of use in the NHTSA's tests. Testers also rate the Marathon's labels, instructions and installation features, and how easy it is to secure the child both forward- and rear-facing.

Review: Child Safety Seat Ease of Use Ratings, Editors of National Highway Traffic Safety Administration


More than 1,700 owners review the Britax Marathon here, giving it an average of 4.7 stars out of 5. The website helpfully distills a list of pros and cons from the reviews, but the only complaint that shows up regularly is that the seat is bulky. Most reviewers praise the Marathon as being durable, comfortable, adjustable, easy to install and easy to clean.

Review: Britax Marathon Convertible Car Seat, Contributors to


The Britax Marathon Classic earns a perfect rating of 5 stars out of 5 in 30 reviews. Owners say it's easy to install and use; they think their child is very safe and seems comfortable.

Review: Untittled

Convertible Car Seats Runners Up:

Britax Advocate 70-G3 Est. $280

7 picks including:, National Highway Traffic Safety Administration…

Cosco Scenera Est. $50

6 picks including:,…

Graco My Ride 65 Est. $135

5 picks including:, Good Housekeeping…

Recaro ProRide Est. $224

5 picks including:, National Highway Traffic Safety Administration…

Combi Coccoro Est. $175

3 picks including:, National Highway Traffic Safety Administration…

Clek Foonf Est. $399

1 pick including:, National Highway Traffic Safety Administration…

Britax Advocate 70-G3 Convertible Car Seat, Onyx
Buy from
New: $379.99 $341.00   
Average Customer Review:  
Cosco Apt 40RF Car Seat, Calvin
Buy from
New: $59.99 $39.00   
In Stock.
Average Customer Review:  
RECARO ProRIDE Convertible Car Seat, Blue Opal
Buy from
New: $299.99 $219.99   
In Stock.
Average Customer Review:  
Combi Cocorro Lightweight Convertible Car Seat, Chestnut
Buy from
New: $239.99 $203.15   
In Stock.
Average Customer Review:  
Clek Foonf 2013 Convertible Car Seat, Blue Moon
Buy from
New: $474.99 $398.00   
In Stock.
Average Customer Review:  

Back to top