The Britax Marathon car seat is designed for worry-free travel. Built with the safety and comfort of your child in mind, the Britax Marathon protects babies and toddlers with a heavy-duty side shell that is able to absorb crash impact. It may be installed forward-facing or rear-facing, with 10 different positions to fit the exact height of your child.

Britax Marathon highlights:

  • Convertible car seat for children 5 pounds to 65 pounds
  • SafeCell impact protection designed to compress in a crash
  • Side impact protection with EPP foam
  • 10-position harness
  • Integrated steel bars
  • Push button latch connectors
  • May be installed rear-facing up to 35 pounds and forward-facing up to 65 pounds and 49 inches tall
  • Removable seat cover is stain-resistant and available in static, azul, confetti, domino, kiwi, onyx, silver cloud, McCoy, summit, and city dots designs
The Britax Marathon car seat has consistently ranked among the best children car seats in the past three years – BabyCenter Moms' Pick in 2014 and BabyGearLab Editor's Choice and SafeWise Recommended in 2016. Although it's a little bit on the expensive side, many parents say the convenience and peace of mind are worth the price.

The Britax Marathon now comes in two versions – the Marathon G4.1 and the Marathon ClickTight.

Both models take the guesswork out of properly fitting your child into a convertible car seat. In both styles, you can install the seat rear-facing for infants 5 pounds to 40 pounds, or forward-facing for toddlers 20 pounds to 65 pounds.

Britax Marathon car seat review

Britax has made it quite easy to secure babies in the Marathon car seat. The harness straps slide effortlessly and are easy to adjust to a particular height, thanks to its no-rethread design. There are 10 harness levels on the Marathon G4.1 model and 12 positions on the ClickTight version, with super thick harness straps that do not twist like those on cheap car seats.

The Britax Marathon is great for toddlers. The shell is quite tall with the top harness slots reaching 17.5 inches. Most kids will fit in the Marathon until they are five or six years old.

If you are traveling with a newborn, you might want to get the Marathon ClickTight which has a minimum harness slot of 7.5 inches. The Marathon G4.1 is higher at 8.5 inches and has only one lower seat pad to fill the extra space in a toddler car seat.

One of the best features of the Britax Marathon is the built-in lock-off clips that keep it tightly installed through traditional seat belts. Just slide the seat belt of your car through the lock-off, tighten the seat in position, and close the lock-off.

The base of the Britax Marathon allows for easy recline adjustments when rear-facing by simply pulling a handle. Soft, plush covers and thick padding provide a comfortable ride for babies and children, with provision for accessories such as cup holder, kick mats, storage pouch, and belly pad.

The Britax Marathon car seat is 26 inches in height and may not fit in compact cars particularly when installed in a rear-facing position. Check the dimensions of your vehicle before purchasing a Britax Marathon.

Top features of the Britax Marathon car seat

Superior Protection
  • Side impact protection from deep side walls lined with energy-absorbing EPP foam distributes crash force, shields from vehicle intrusion, and protects the head, neck and body of your child.
  • SafeCell technology designed to compress the seat during a crash and lower the center of gravity so the child doesn't propel forward toward the front seat
  • Integrated steel bars keep the seat connected to the vehicle and reduce forward flexing during a crash
  • Patented Versa Tether diverts energy away from your child as the staged-release tether webbing slows down the forward movement and a two-point attachment minimizes forward rotation while anchoring the top of the child seat.
  • Anti-rebound bar limits the rotation of a rear-facing installed car seat during a crash.
  • Tangle-free, 5-point Harness Ultra Guard System (HUGS) provides resistance to forward movement in the event of a crash.
  • Anti-slip contoured base keeps the car seat in place while offering optimum vehicle fit.

Easy Installation

  • Push button latch connectors lock the seat into place with one click.
  • Built-in lock-offs ensure a tight vehicle seat belt installation with minimal effort.
  • 3 recline positions make it easy to find the proper angle for seat installation.
  • Quick-adjust harness adjusts shoulder height without removing the harness straps
  • Easy to remove cover allows for easy cleaning without taking the harness or the car seat out.
  • Premium LUAS connectors with easy-release push button
  • Built-in lock-offs ensure a tight installation with traditional lap and shoulder seat belts
Maximum Fit and Comfort
  • 10-position, quick-adjust harness ensures a comfortable fit as your child grows with no re-threading necessary.
  • Maximum 65-pound (29.4 kg) weight capacity and two-buckle positions for growing kids.
  • Rear-facing and forward-facing reclining options to achieve most comfortable position
  • High-density foam cushions your child with an extra layer of padding
  • EZ-Buckle system keeps buckles and straps out of your way when placing your child in the Marathon car seat.
  • Infant positioning pillow provides extra comfort while adjusting proper harness fit for small babies.
Room for Accessories

The Britax Marathon lets you add a child cup holder, kick mats, storage pouch, vehicle seat protector, back seat mirror, EZ-Buckle belly pad, and waterproof seat liner.


Minimum effort installation, convenient and versatile adjustments, and maximum comfort and safety make the Britax Marathon car seat an excellent choice for travelling with the young ones.