rigsize

Keystone Alpine 3910RK mattress size

Years 2021–2027Sold as AlpineLength 42 ft 10 inSleeps 6
70 in 80 in
To scale. Dashed: a regular queen.
Main bed70 × 80 inRV king

That's an RV king, 6 in narrower than a regular king (76 × 80 in). A regular king won't fit, so get an RV king in exactly 70 × 80 in.

About the RV king size →

Keystone 2024 brochure, 2024.

Mattresses in 70 × 80 in

We may earn a commission when you buy through some of these links. It doesn't change which mattresses we list.

Great all around
RVMattress.com Signature Hybrid

RVMattress.comSignature Hybrid

  • Hybrid
  • 13.25 in thick
  • Soft / Medium / Firm

Sleep Foundation: Best Mattress Overall Read review

$1,865RV King - 70x80 · list priceSee price
Best value
RVMattress.com CopperFlex Essential

RVMattress.comCopperFlex Essential

  • All-foam
  • 6 in thick
  • five comfort options
$799RV King - 70x80 · list priceSee price
Firm
RVMattress.com Plank Firm Luxe

RVMattress.comPlank Firm Luxe

  • Hybrid
  • 13 in thick
  • Firm / Extra Firm
$1,865RV King - 70x80 · list priceSee price
Cooling
RVMattress.com Aurora Luxe Cooling

RVMattress.comAurora Luxe Cooling

  • Hybrid
  • 13.25 in thick
  • Soft / Medium / Firm

Sleep Foundation: Best Mattress for Temperature Regulation Read review

$2,465RV King - 70x80 · list priceSee price
RV hybrid
RVMattress.com CopperFlex RV Hybrid

RVMattress.comCopperFlex RV Hybrid

  • Hybrid
  • 10 in thick
  • Medium-Firm
$1,065RV King - 70x80 · list priceSee price
Custom size
Mattress Insider Luxury Gel Memory Foam

Mattress InsiderLuxury Gel Memory Foam

  • Memory foam
  • 8 in thick
  • not stated
Made to 70 × 80 inGet a quote
Bedroom in a Alpine

The Alpine bedroom. Measure the platform, not the old mattress, before you buy.

Bed sizes by year

YearMain bedBunksOther bedsSource
202170 × 80 in King––Keystone 2021 brochure
202470 × 80 in King––Keystone 2024 brochure

Years not listed weren't published.

The 3910RK floorplan

Keystone Alpine 3910RK floorplan, 2027

Keystone's 2027 3910RK floorplan.

Is this your 3910RK?

Check the year and length against your RV before you order.

YearModelLengthSleeps
2021Alpine 3910RK43 ft 0 in6
2022Alpine 3910RK43 ft 0 in6
2023Alpine 3910RK42 ft 11 in6
2024Alpine 3910RK42 ft 11 in6
2025Alpine 3910RK42 ft 11 in6
2026Alpine 3910RK42 ft 11 in6
2027Alpine 3910RK42 ft 10 in6

Other Alpine mattress sizes

Sources

  1. Keystone (keystonerv.com): https://www.keystonerv.com/product/alpine/luxury-fifth-wheels/floorplans/3910RK

Questions

What size mattress is in the Keystone Alpine 3910RK?

The main bed is 70 × 80 in (Keystone 2024 brochure, 2024).