The Birkenstock Siena Big Buckle in Dusty Blue Oiled Leather is a premium, stylish variant of the classic crossover-strap sandal. Below is a detailed description of its design, materials, and fit.
The Siena is distinguished by its elegant crossover straps, offering a more refined and feminine aesthetic compared to the traditional two-strap Arizona. The "Big Buckle" version elevates this look with oversized, high-shine hardware.
Model: Siena Big Buckle
Color: Dusty Blue (a soft, muted denim-blue tone)
Upper Material: Oiled Nubuck Leather. This is a thick, high-quality leather with an untreated surface that develops a unique patina over time. The oiled finish gives it a "lived-in" look and makes the color vary slightly between pairs.
Footbed: Semi-Exquisite. Unlike the standard suede footbed, this version features a contoured cork-latex footbed completely wrapped in soft, smooth leather that is color-coordinated to match the Dusty Blue upper.
Buckle: Oversized adjustable metal pin buckle in a silver-tone finish.
Sole: Lightweight EVA (Ethylene Vinyl Acetate) for cushioning and shock absorption.
Origin: Made in Germany.
Anatomical Support: Features the legendary Birkenstock footbed which includes a deep heel cup, longitudinal and transverse arch supports, and a roomy toe box. It is designed to mold to the shape of your foot with wear.
Premium Aesthetics: The combination of the matte oiled leather and the large, polished buckle makes this sandal suitable for both casual wear and more dressed-up summer outfits.
Durability: Oiled leather is known for its durability and weather resistance; minor scuffs can often be rubbed out with your thumb or a leather conditioner.
EU Size 36: Typically converts to a US Women's 5–5.5.
Footbed Width: This model is commonly sold in the Narrow Fit (indicated by a filled-in foot icon on the footbed), which is Birkenstock's standard width for women's fashion styles, fitting most medium-to-narrow feet.
Feel: Because the footbed is wrapped in smooth leather (Semi-Exquisite), it feels cooler and sleeker against the skin than the traditional fuzzy suede lining.
To maintain the Dusty Blue finish:
Apply a leather conditioner or "mink oil" sparingly if the leather looks dry (note: this may slightly darken the blue).
Avoid soaking in water; if they get wet, air dry them away from direct heat.
Use a cork sealer occasionally to prevent the exposed cork sides from drying out or cracking.