King Great Value Mattresses Compatible with Adjustable Bed Base | Flex‑Friendly Foam, Latex & Hybrid Serta Mattresses

King mattresses measure 76" × 80" — the widest standard size, giving each partner the same personal space as a twin. They're the top choice for couples who want maximum room, families who co-sleep, and larger master bedrooms. Compare every king option below by brand, feel, and price.
Great Value mattresses deliver dependable comfort and support at our most affordable prices — a smart pick for guest rooms, kids' rooms, students, and budget-minded shoppers. Compare every great-value option below by brand, type, and feel.
These mattresses are built to flex with adjustable bed bases — bending smoothly at the head and foot without damage — so you can raise, recline, and find your ideal position. Compare every adjustable-base-compatible option below by brand, type, and feel.

Serta is a globally recognized mattress brand celebrated for its comfort-first designs and sleep innovations. With over 90 years of experience, Serta continues to deliver quality mattresses that Canadians can trust.

Shop 200+ mattresses from Serta, Beautyrest, Sealy, Tempur-Pedic, Springwall, and Stearns & Foster at National Mattress — available in Single/Twin through King sizes from $99 to $6,640. Choose from innerspring, euro-top, memory foam, hybrid, and latex constructions in four firmness levels from extra firm to plush. Every mattress is manufactured in Canadian factories using CertiPUR-US® certified foams and ships free across Canada with a 365-night sleep trial, price match guarantee, and manufacturer warranty coverage up to 25 years.

King Great Value Mattresses Compatible with Adjustable Bed Base | Flex‑Friendly Foam, Latex & Hybrid Serta
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  • SERTA® Modern Series™ 8" Medium Firm Gel Foam Mattress - King SERTA® Modern Series™ 8" Medium Firm Gel Foam Mattress - King brand icon
    • 8 Inch Model with Double Layers of Comfort
    • Serta CoolWick Breathable Cover
    • PureComfort Gel Foam with PureComfort Foam Support Core
    • Designed and Built in Canada
    King In stock for fast delivery $653
    Compare at $1,499
    Online availability icon In-Stock Only 2 left!
    In-Store availability icon On Display:
    Free delivery availability icon Free delivery as soon as Tomorrow, Jun 10
    Pickup available icon Only Pickup available to
  • SERTA® Classic® 10" Firm Tight Top Mattress - King SERTA® Classic® 10" Firm Tight Top Mattress - King brand icon
    • 800 Edition Custom Support Coil System
    • 3 Zone Body Support
    • Serta® Support Foam
    • Serta® Anti-Microbial Fibre Technology
    • Serta® Best Edge® Foam Encasement
    • Designed and Made in Canada
    King $699
    Compare at $1,799
    Online availability icon Backorder Available
    In-Store availability icon On Display:
    Estimated delivery icon Estimated free delivery on Tuesday, Jun 23
  • OPEN BAG - SERTA® Modern Series™ 10" Medium Firm Gel Foam Mattress - King OPEN BAG - SERTA® Modern Series™ 10" Medium Firm Gel Foam Mattress - King brand icon
    • 10 Inch Model with Double Layers of Comfort
    • Serta CoolWick Breathable Cover
    • PureComfort Gel Foam with PureComfort Foam Support Core
    • Designed and Built in Canada
    King In stock for fast delivery $711
    Compare at $1,799
    Online availability icon In-Stock Only 1 left!
    In-Store availability icon On Display:
    Free delivery availability icon Free delivery as soon as Tomorrow, Jun 10
    Pickup available icon Only Pickup available to
  • SERTA® Modern Series™ 10" Extra-Firm Gel Foam Mattress - King SERTA® Modern Series™ 10" Extra-Firm Gel Foam Mattress - King brand icon
    • 10 Inch Model with Double Layers of Comfort
    • Serta CoolWick Breathable Cover
    • PureComfort Gel Foam with PureComfort Foam Support Core
    • Designed and Built in Canada
    King $765
    Compare at $1,799
    Online availability icon Backorder Available
    In-Store availability icon On Display:
    Estimated delivery icon Estimated free delivery on Tuesday, Jun 23
  • SERTA® Modern Series™ 10" Medium Firm Gel Foam Mattress - King SERTA® Modern Series™ 10" Medium Firm Gel Foam Mattress - King brand icon
    • 10 Inch Model with Double Layers of Comfort
    • Serta CoolWick Breathable Cover
    • PureComfort Gel Foam with PureComfort Foam Support Core
    • Designed and Built in Canada
    King $765
    Compare at $1,799
    Online availability icon Backorder Available
    In-Store availability icon On Display:
    Estimated delivery icon Estimated free delivery on Tuesday, Jun 23
  • SERTA® Classic® 11" Plush Euro Top Mattress - King SERTA® Classic® 11" Plush Euro Top Mattress - King brand icon
    • 800 Edition Custom Support Coil System
    • 3 Zone Body Support
    • Serta® PillowSoft® Foam
    • Serta® Anti-Microbial Fibre Technology
    • Serta® Best Edge® Foam Encasement
    • Designed and Made in Canada
    King $795
    Compare at $1,899
    Online availability icon Backorder Available
    In-Store availability icon On Display:
    Estimated delivery icon Estimated free delivery on Tuesday, Jun 23
  • SERTA® Classic® 11.5" Extra-Firm Tight Top Mattress - King SERTA® Classic® 11.5" Extra-Firm Tight Top Mattress - King brand icon
    • 800 Edition Custom Support Coil System
    • 3 Zone Body Support
    • Cool Twist® Gel Memory Foam + Serta® Support Gel Foam
    • Serta® Anti-Microbial Fibre Technology
    • Serta® Best Edge® Foam Encasement
    • Designed and Made in Canada
    King $885
    Compare at $2,099
    Online availability icon Backorder Available
    In-Store availability icon On Display:
    Estimated delivery icon Estimated free delivery on Tuesday, Jun 23
  • SERTA® Classic® 12.5" Medium Euro Top Mattress - King
    BEST IN CLASS TOP RATED LIMITED STOCK
    SERTA® Classic® 12.5" Medium Euro Top Mattress - King SERTA® Classic® 12.5" Medium Euro Top Mattress - King brand icon
    • 800 Edition Custom Support Coil System
    • 3 Zone Body Support + Serta® Support Gel Foam
    • Cool Twist® Gel Memory Foam + Serta® PillowSoft® Foam
    • Serta® Anti-Microbial Fibre Technology
    • Serta® Best Edge® Foam Encasement
    • Designed and Made in Canada
    King $922
    Compare at $2,199
    Online availability icon Backorder Available
    In-Store availability icon On Display:
    Estimated delivery icon Estimated free delivery on Tuesday, Jun 23
  • SERTA® Classic® 12.5" Luxury Plush Euro Top Mattress - King SERTA® Classic® 12.5" Luxury Plush Euro Top Mattress - King brand icon
    • 800 Edition Custom Support Coil System
    • 3 Zone Body Support 
    • Cool Twist® Gel Memory Foam + Serta® PillowSoft® Gel Foam
    • Serta® Anti-Microbial Fibre Technology
    • Serta® Best Edge® Foam Encasement
    • Designed and Made in Canada
    King $922
    Compare at $2,199
    Online availability icon Backorder Available
    In-Store availability icon On Display:
    Estimated delivery icon Estimated free delivery on Tuesday, Jun 23

9 Items

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