Britax Boulevard vs Advocate vs Marathon Convertible Baby Car Seat

In this comparison report, you are going to finally figure out what the main differences are between Britax Boulevard, Britax Advocate, and Britax Marathon convertible baby car seats. They are built from the same shell and come with similar designs and structures, yet there are a few key differences that Britax has left off in one or two of these models to justify the price difference.

Looking at the table closely, you should be able to identify the main differences between the 3 convertible baby car seats. Continue reading below the table to get a detailed explanation of each of these models and find out which model is best among them.

Britax BoulevardBritax AdvocateBritax Marathon
Extended Leg RoomNoNoNo
Front Facing InstallationClicktight InstallationClicktight InstallationClicktight Installation
Rear Facing InstallationClicktight Installation with LATCHClicktight Installation with LATCHClicktight Installation with LATCH
Dimensions23″ x 18.5″ x 23.723″ x 20.5″ x 23.5″23″ x 18.5″ x 23.7
Weight (lbs)29.430.128.5
5 Point HarnessYes with Click N SafeYesYes with Click N Safe
Harness PaddingHugs With SafecellHugs With SafecellHugs With Safecell
Adjustable Headrest14 positions quick-adjust harness & headrest14 positions quick-adjust harness & headrest14 positions quick-adjust harness & headrest
Cup HolderCan be purchased SeparatelyCan be purchased SeparatelyCan be purchased Separately
Fabric FeaturesFlame Retardant, Safewash, Cool Flow, Clean Comfort, Stay CleanFlame Retardant, Safewash, Cool FlowFlame Retardant, Safewash, Cool Flow, Dual Comfort
Front Facing Weight Limit22-65 lbs.22-65 lbs.22-65 lbs.
Rear Facing Weight Limit5-40 lbs.5-40 lbs.5-40 lbs.
High Back Booster Weight LimitNot availableNot availableNot available
Backless Booster Weight LimitNot availableNot availableNot available
Recline Positions7-Position, Quick-Adjust Recline7-Position, Quick-Adjust Recline7-Position, Quick-Adjust Recline
Safety FeaturesSafecell technology + V-Shaped TetherSafecell technology + V-Shaped TetherSafecell technology + V-Shaped Tether
Side impact protection2 Layers – energy-absorbing shell + foam-lined headrest surround the head, neck, and torso.3 layers of side impact protection surround the head, neck, and torso1 Layer – Energy-absorbing shell surrounds your child’s head, neck, and torso
Stroller CompatibilityNoNoNo
Build MaterialHigh Strength Steel FrameHigh Strength Steel FrameHigh Strength Steel Frame
Anti Rebound BarOptionalOptionalOptional
Removable CoverYes, Easy RemoveYes, Easy RemoveYes, Easy Remove
Washable CoverYesYesYes
Harness Storage CompartmentYesYesYes
Removable Plush Head & Body InsertsYesYesYes
Level IndicatorsYesYesYes
Average Customer Rating4.8 out of 54.8 out of 54.8 out of 5
Where to BuyClick here for priceClick here for priceClick here for price

The Similarities

Clicktight Installation

The Clicktight installation system is one of the simplest approaches for parents to date. Britax has outdone itself in many aspects of the baby car seats, strollers, and more with their patented features like the Clicktight, Click N Safe system, and many more.

The Britax Advocate, Marathon, and Boulevard all come with Clicktight installation systems in the front-facing and rear-facing modes.

All you have to do is lift the bottom cover, pass the belt through the color-coded guide (different for front-facing and rear-facing modes) and close the bottom seat cover again until you hear a click. The rear facing installation includes Clicktight technology with LATCH installation.

Move the seat around to make sure everything is tight and secure. For further understanding, watch the video below on Clicktight installation for front-facing and rear-facing modes in Britax Boulevard, Marathon, and Advocate convertible car seats.

Clicktight installation with LATCH – Forward-facing mode


Clicktight installation with LATCH – Rear-facing mode

Convertible 2 in 1 Option

Unlike Britax One4Life which supports a growing child weighing up to 120 lbs, the Britax Marathon, Boulevard, and Advocate support up to 65 lbs. They are convertible car seats that can be used only in the front and rear-facing modes.

You will later have to invest in a high-back or backless booster car seat for your child weighing more than 65 lbs.

No Cup Holders Buy Separately

One of the most disliked features of these convertible car seats is the missing cup holder, especially considering their prices. A cup holder has become a standard and required feature in baby car seats and Britax chose to skip these in the Marathon, Boulevard, and Advocate models, making them optional investments.

You can purchase these cup holders separately and install them in any of the three car seats compared here. The Britax Advocate, Boulevard, and Marathon support up to 2 cup holders which can be installed and removed as needed.

Click here to get the price on cup holders for these Britax car seats >

SafeCell Protection with Steel Frame

SafeCell is another creative and unique technology implemented in Britax car seats, including the Britax Advocate, Boulevard, and Marathon. The SafeCell is located at the base of the car seat as you can see from the video below.


This honeycomb grid-like structure turns into a crumple zone which absorbs the crash energy in the case of impact, providing additional safety for your child.

When combined with the steel reinforced frame that holds the 5-point harness, these Britax convertible models rate very high when it comes to safety standards. They do a great job of surpassing industry standards at the same time.

14 Position Headrest and 7 Position Recline Options

The child’s head and shoulders should be well rested on the headrest – this is where the safety and comfort of the car seat kick in. Some car seats have limited headrest options which can leave wiggle space causing discomfort to your baby.

A 14-position adjustable headrest does wonders on the other hand. With multiple stops, the headrest in the Britax Boulevard, Marathon, and Advocate is always in the perfect position to support your baby for maximum comfort and safety at the same time.

The same can be said for 7-position recline options that can be found in all 3 of the Britax convertible car seats compared on this page.

Washable and Flame Retardant Fabric

Most baby car seats tend to have removable covers but you can only do so by releasing the car seat from the vehicle.

The Britax Marathon, Advocate, and Boulevard come with quick remove covers. You can remove them without removing the harness from the car seat.

Watch the video below to see how easy it is to remove the cover from the Britax convertible car seat. The process is the same for Britax Advocate, Boulevard and Marathon car seats. These covers can be machine washed and dried – not to mention they are also flame retardant and top-rated for breathability.


Anti Rebound Bar

The Anti Rebound bar is an essential addon to the baby car seat which adds next-level protection for your child in the back seat of your vehicle. It absorbs the rebound impact in the event of a crash protecting the car seat from bouncing front to back.

The Britax Convertible Clicktight series including Marathon, Boulevard, and Advocate does not come with the Anti Rebound Bar installed, but you can choose it as an optional add-on on purchase. 

The Differences

Side Impact Protection

This is the most advertised feature by Britax to justify the price difference between Advocate, Boulevard, and Marathon car seats. The Marathon is the barebone model that comes with a single level of side impact protection – the energy-absorbing foam lining.

The Britax Boulevard comes with 2 layers of side impact protection. One is the energy-absorbing foam similar to Britax Marathon, but you also get additional padding foam-lined headrest for extra safety.

As you can see from the image above, the Britax Advocate includes 3 layers of side impact protection – Energy Absorbing Foam, the foam-lined headrest, and the Outer Impact shell protecting the headrest. This feature comes in handy by protecting the child against shards and shattered glass pieces in the air in the event of an impact.

  • Britax Marathon: 0
  • Britax Boulevard: 0.5
  • Britax Advocate: 1

Click N Safe

When adjusting the 5-point harness, you need to make sure the child is tightly secured by the straps without leaving any gaps. You need to adjust the strap a few times on the first few attempts to make sure it’s perfectly secure.

The Click N Safe is a unique feature that you can find in the Britax Advocate and the Boulevard but not in the Marathon. When adjusting the 5-point harness, you hear a click sound from the Click-N-Safe that indicates that the child is now perfectly secured by the harness.

It’s an automatic harness adjustment indicator, a time-saving feature for parents. You can keep tightening the harness and the Click-N-Safe will keep emitting a click sound to notify you that the straps are tight enough already.

  • Britax Marathon: 0
  • Britax Boulevard: 1
  • Britax Advocate: 1

Harness Grip

In the event of a crash or a sudden brake, the child would get pulled forward before bouncing back. The shoulder and chest straps of the harness make sure the child doesn’t get disturbed or troubled, but with a tightly installed strap, the baby can start feeling the discomfort of the straps edging on their body.

As you can notice from the image above, the 5-point harness includes a padded grip also known as HUGS which lay over the child’s chest to prevent forward movement or bounce without facing discomfort.

The grip texture on the HUGS of Britax Marathon looks pretty basic, while the grip texture on the HUGS of Britax Advocate and Boulevard looks spongy and comfortable for the child.

  • Britax Marathon: 0
  • Britax Boulevard: 1
  • Britax Advocate: 1


Final Score Points

  • Britax Marathon: 0
  • Britax Boulevard: 2.5
  • Britax Advocate: 3

The scorecard speaks for itself.

The Britax Advocate is the obvious winner here with the most features.

The Britax Boulevard comes in a close second with just the same features but loses half a point for 2 layers of side impact protection when compared to the Advocate. It is still an excellent choice if the 3rd layer of protection is not compulsory in your criteria.

The Britax Marathon is the barebone model with basic protection, comfort, and safety options. It’s not a bad option in any way, but when compared to Britax Boulevard and the Britax Advocate, the Britax Marathon is clearly at a loss.


Abi, a devoted researcher, compares baby products to empower parents. With unbiased insights on car seats, monitors, and more, Abi's concise style helps navigate the overwhelming world of baby products. Choose wisely with Abi's guidance.

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