Britax Boulevard vs. Marathon vs. Advocate: Car Seat Comparison

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 This article was reviewed by Amanda Brown, CPST.

If you’ve spent any time browsing car seats or strollers, you’ve probably heard of Britax. That’s because the brand offers an extensive line of baby gear for transporting your little one wherever you need to go. 

But when a reputable brand offers so many solutions, how do you choose the right option for your family? Rest easy knowing all car seats sold in the United States are safe to use. Then, take a hard look at the specs—all of the added safety and convenience features, comfortability and overall value—to determine what suits your family the best. 

To help you on your way, we asked our gear experts to test and review the most sought-after Britax convertible car seats in the brand’s ClickTight line—seats with a patented easy installation system—against one another. Without further ado, the Britax Boulevard vs. Marathon vs. Advocate.

Table of Contents 

• Main Differences
• Britax Advocate ClickTight: Pros and Cons 
• Britax Marathon ClickTight: Pros and Cons
• Britax Boulevard ClickTight: Pros and Cons
• Specs & Comparison Chart
• Price Comparison
• Weight & Dimensions Comparison
• Height & Weight Limits Comparison
• Safety Comparison
• Installation Comparison
• How to Choose

Britax Advocate vs. Marathon vs. Boulevard: Main Differences 

The Britax Advocate, Marathon and Boulevard are all convertible car seats that are part of the brand’s ClickTIght line. And while they are very similar seats, there are a few key differences. 

Namely, the Advocate has extra padding for enhanced safety, which makes it the most expensive pick. The Marathon, the cheapest of the three, only has a single layer of padding, but is a smaller seat—great for small cars. The Boulevard falls somewhere in the middle—it has the same small footprint as the Marathon, but also has a second layer of side impact protection. 

Britax Advocate ClickTight: Pros and Cons

• Amazon Price: $399.99
• Retail Price: $399.99
• Avg. GoodBuy Gear Price: $209
• Weight: 30.6 lbs 
• Dimensions: 23 x 20.5 x 23.5 inches

• Child Height Limit: 49 inches or less
• Rear Facing Weight Limit: 5 to 40 pounds
• Forward Facing Weight Limit: 20 to 65 pounds

All Britax ClickTight seats have an important claim to fame: The patented installation system makes it easier and faster to install your car seat with confidence. They also have super strong steel frames to stabilize the seat on impact and V-shaped tethers to reduce both rotation and forward movement in the event of an accident. The Britax Advocate ClickTight also has a 14-position quick-adjust harness system, so you can easily adjust the whole thing without re-tethering as your child grows. 

Where the Advocate differs is in padding. The seat has three full layers of side impact protection—an energy-absorbing shell, side cushions and a quick-adjust headrest—to offer more head and neck protection. And while this machine-washable padding helps improve your child’s comfort and give parents peace of mind, it’s worth noting that it makes the seat a bit bulkier than the other two. Make sure to check the dimensions against your car before purchasing—especially if you’re seating multiple kiddos in car seats. And though there’s only a $60 delta, it’s also the most expensive of the three.

Best for: Parents who want as many safety features as possible

Pros 

• Three full layers of side impact protection
• Machine-washable cover
• Easy install
• Grows with your little one

Cons 

• Most expensive of the three
• No cup holder
• Heaviest of the three

Britax Marathon ClickTight: Pros and Cons

• Amazon Price: $339.99 
• Retail Price: $339.99
• Avg. GoodBuy Gear Price: $224
• Weight: 27 lbs 
• Dimensions: 23 x 18.5 x 23.7 inches 

• Child Height Limit: 49 inches or less
• Rear Facing Weight Limit: 5 to 40 pounds
• Forward Facing Weight Limit: 20 to 65 pounds

Like all of the convertible car seats in the Britax ClickTight line, the Marathon secures to your vehicle using the brand’s ClickTight Installation System, making installation both easier and safer. The seat itself goes above and beyond federal safety standards, too. It has an energy-absorbing shell that’s equipped with a single layer of foam padding for improved side impact protection—ideal for protecting your child’s head. It also has a patented V-shaped tether to minimize side-to-side seat rotation and forward movement if you do get into an accident. 

Like the other two car seats in this line, the Marathon ClickTight is a great choice for parents who don’t want to purchase multiple car seats over the course of their little one’s life, since it’s designed to grow with your child. It has seven recline angles, complete with an automatic level indicator to take the guesswork out of alignment. Plus, the 14-position harness is exceptionally easy to adjust.

Parents with multiple kiddos or small cars will love the fact that the Britax Marathon ClickTight convertible car seat is also the lightest and smallest of the three seats in comparison. Plus, it’s outfitted with a machine-washable cover—perfect if your little one tends to get car sick or likes to snack on long rides.

Best for: Price-conscious families and/or parents will small cars or multiple kiddos 

Pros 

• Easy install
• Light and compact
• Machine-washable cover
• Most affordable of all three
• Grows with your little one

Cons 

• No cup holder
• Least amount of padding of all three

Britax Boulevard ClickTight: Pros and Cons

• Amazon Price: $369.99
• Retail Price: $369.99
• Avg. GoodBuy Gear Price: $207
• Weight: 29.4 lbs 
• Dimensions: 23 x 18.5 x 23.7 inches

• Child Height Limit: 49 inches or less
• Rear Facing Weight Limit: 5 to 40 pounds
• Forward Facing Weight Limit: 20 to 65 pounds

Now, for the happy medium of the Britax ClickTight seats. The Boulevard ClickTight has all of the same safety features—the impact-absorbing base, steel frame and compatible anti-rebound bar—as the Britax Marathon. But it’s one tiny step above, thanks to a second layer of side impact protection for your child’s head. (The Advocate has three layers.) It also has similar features we consider nice to have, including well-padded seats for your child’s comfort and machine-washable fabrics for your convenience. Of course, The Boulevard also has the same ease of use as other ClickTight seats, plus grows with your child. 

So what’s the differentiating factor? It’s the middle-tier side impact protection that places the Boulevard smack in the middle of the other two models. It isn’t the most protective, but it isn’t the least, either. And because of this mid-tier protection, it isn’t the heaviest seat, but it also isn’t the lightest. This is also reflected in the price of the car seat. The Boulevard is about $30 more expensive than the Marathon and around $30 less expensive than the Advocate.

If you’re willing to make some sacrifices, but don’t necessarily want the most cost-effective choice, the Boulevard is a good option for you.

Best for: Families who want more safety features, but don’t want the most expensive or largest seat

Pros 

• Easy install
• Two layers of side impact protection
• Machine-washable cover
• Grows with your little one

Cons 

• No cup holder
• Not the lightest, nor the cheapest

Boulevard vs. Marathon vs. Advocate: Specs & Comparison Chart 

Price Comparison 

As far as convertible car seats go, all three models are relatively expensive. But the cost is justified, thanks to exceptionally easy installation, added safety features like side impact protection and a wide range of recline and headrest/harness positions. Though the Boulevard, Advocate and Marathon are all within $60 of one another, the Marathon is the cheapest, followed by the Boulevard and then the Advocate.

Winner: Britax Marathon ClickTight

Weight & Dimensions Comparison 

All convertible car seats are larger and bulkier than infant car seats, but exact sizes vary from model to model—even among Britax ClickTight models. The Britax Boulevard and Marathon are the same size—23 x 18.5 x 23.7 inches—while the Advocate is a few inches larger all around at 23 x 20.5 x 23.5 inches. The three models all weigh a few pounds of one another: The Marathon weighs 27 pounds, the Boulevard weighs 29.4 pounds and the Advocate weighs 30.6 pounds.

Winner: Britax Marathon ClickTight

Height & Weight Limits Comparison 

If you’re considering these three seats, here’s a bit of good news: All three seats will grow with your child in exactly the same way. All weight and height limits are exactly the same, plus each seat has the same seven recline positions and a 14-position harness.

Winner: A three-way tie between the Advocate, Boulevard and Marathon

Safety Comparison 

First and foremost, it’s important to note that all three of these seats are regarded as exceptionally safe seats. They all have features above and beyond federal safety standards, including steel frames, impact-absorbing bases and added side impact protection. That said, the Advocate edges out in terms of safety, thanks to its three full layers of side impact protection. In comparison, the Boulevard has two and the Marathon has one.

Winner: Britax Advocate ClickTight

Features Comparison

All three models—the Marathon, Boulevard and Advocate—are ripe with added safety and convenience features. They all have steel frames, impact-absorbing bases and added side impact protection for safety. All three seats also have the same easy ClickTight technology for easy installation, plus seven recline positions and a 14-position harness to grow with your little one. 

Just as sweet: All seats also have plush machine-washable seats for your sanity and your child’s comfort. If you had to pick a winner, though, it would be the Advocate, since it has additional layers of side impact protection.

Winner: Britax Advocate ClickTight

Installation Comparison 

Ease of installation is another attribute you can rule out while deciding between these three convertible car seats—all three use the same ClickTight technology that offers a convenient alternative to the limitations of the LATCH system (namely, LATCH systems cannot be used to install convertible car seats for the entirety of their useable lives.)

Note: Always reference the car seat manual and vehicle owner's manual when installing your car seat.

Winner: A three-way tie between the Advocate, Boulevard and Marathon

Britax Advocate vs. Marathon vs. Boulevard: How to Choose 

First, something to ease the busy mind: the Britax Marathon, Boulevard and Advocate are all safe seats for your little one. They are some of the best car seats because they feature tons of high-quality safety features to keep your child safer while riding in the car—especially in the event of a crash. They’re also highly rated for comfort and convenience, thanks to the patented installation system, easily adjustable harnesses, multiple recline positions and machine-washable fabric. Plus, the fact that all three seats grow with your child.

As noted, there are subtle differences that account for the ~$60 price differentiation between the least expensive Britax Marathon ClickTight and the most expensive Britax Advocate ClickTight. Namely, the Marathon has just one layer of side impact protection, while the Advocate has three. The Boulevard ClickTight falls in the middle with two layers.

But that doesn’t necessarily make the Advocate the easy best choice. The Advocate is the heaviest and the bulkiest because of the padding, so it may not be suitable for large families who seat multiple kids in one row or those with small cars. 

To simplify it: 

• If additional safety features are your chief concern, opt for the Advocate. 
• If price is your biggest consideration, try the Marathon. 
• If you need a slimmer seat but want as many safety features as possible, go with the Boulevard. 

If you're looking for a car seat with great overall value, any of these seats will suit you just fine, but if you want to make an easy decision between the three, opt for the Britax Advocate if you want as many additional safety features as possible, the Britax Marathon if you need something more budget-friendly and the Britax Boulevard if you want a happy medium.