Floor plan
Double Slide
Two-slide layout with front lounge, central galley, and rear bedroom
Click to enlarge
2026 Marathon Coach
2026 Marathon X3-45 Conversion for Sale
We don't sell this from a lot. RVBrokers is a buyer's agent, so we help you find, price, and negotiate this model wherever it is, and line up an inspection before you pay.
Marathon's conversion on Prevost's X3-45 chassis — the same luxury, a distinctly different shell.
The X3-45 is the other half of Marathon's new-build lineup, converting Prevost's X3-45 chassis into a full custom luxury coach. Mechanically it shares the family's commercial-grade bones — a Volvo D13 diesel and Allison six-speed on a heavy air-suspension chassis — but the X3-45's body and window architecture give it a different stance and interior light than the H3-45. Marathon's current X3-45 builds feature double-slide layouts, Crestron-controlled surround sound and automation, and off-grid power support for living away from shore power. Like every Marathon, each X3-45 is a numbered, one-off build finished to the owner's specification. For buyers who prefer the X3-45 platform — or who find the right one in inventory — it delivers the same hand-built Marathon luxury in a different package.
Looking for a Marathon X3-45 Conversion for sale?
You're in the right place. We don't sell the X3-45 Conversion off a lot — we work for you, find the cleanest one on the market new or used, inspect it, and negotiate it. Below is everything you need to know before you shop: the real specs, every floor plan, the photos, what it tends to sell for, and a straight read on what owners love and what they grumble about.
Gallery
X3-45 Conversion — inside & out
Specs
X3-45 Conversion specifications
Length45'
Sleeps4 – 6
Bathrooms1 – 1.5
ChassisPrevost X3-45, air suspension
EngineVolvo D13 500 HP Diesel
TransmissionAllison 6-speed Automatic
GeneratorDiesel generator (coach-specific)
StorageFull pass-through basement bays
Specs reflect the 2026 model year and can vary by floor plan and options.
Floor plans
2 X3-45 Conversion floor plans
Tap any diagram to see the full layout. The floor plan you choose changes the sleeping setup, bath, and storage — it's the single biggest decision on this coach.
Click to enlargeFloor plan
Custom
Bespoke layout configured to the owner's specification on the X3-45 shell
Click to enlargeOwner verdict
What buyers love and what to watch
What buyers love
- Same commercial-grade Marathon engineering on an alternative Prevost platform.
- Crestron automation and surround sound integrated coach-wide.
- Off-grid power support extends where you can comfortably stay.
What to watch
- Still a seven-figure, fully custom build — no off-the-lot pricing.
- A big diesel bus to drive, park, and service; not for casual RVers.
- Fewer new X3-45 builds than H3-45 of late, so check current inventory.
Notable features
- Built on Prevost's X3-45 chassis for a distinct body and interior-light character
- Double-slide layouts with Crestron-controlled surround sound and automation
- Off-grid power support for camping away from shore power
- Volvo D13 diesel and Allison six-speed shared with the H3-45
More from Marathon
Compare other Marathon Coach models
Questions
Marathon X3-45 Conversion — buyer FAQs
How much does a Marathon X3-45 Conversion cost?
New builds start around $3 million; pre-owned X3-45 coaches range from the mid six figures up. Price swings hard on year, mileage, slide count, and condition, so treat that as a starting point — tell us the exact coach you're eyeing and we'll get you the real number.
Is the X3-45 Conversion gas or diesel?
Diesel. It runs a Volvo D13 500 HP Diesel on a Prevost X3-45, air suspension chassis.
How big is the X3-45 Conversion?
It's 45' long and sleeps 4 – 6. There are 2 floor plans to choose from.
Should I get a used X3-45 Conversion inspected before I buy?
Yes — every time. Our independent inspectors check the roof, slides, levelers, and chassis before money moves, and our buyer's agents use anything they find to negotiate the price down.
Talk to a human
Ready to find your X3-45 Conversion?
Tell us the floor plan and budget you want. We'll hunt the best one for sale, inspect it, and negotiate it — entirely on your side.