The defining strap on a Mary Jane can make a shoe feel more secure than a plain flat, but its position matters. A strap across the forefoot behaves differently from one high on the instep. Before choosing the style, see where the strap lands on your foot and how much adjustment remains.
Fasten both shoes at a comfortable setting while standing. The strap should help hold the shoe without forcing the foot downward or leaving a painful edge. If only the tightest hole works, or even the loosest feels restrictive, compare another size or model rather than assuming a new hole will solve everything.
Walk and bend through a step. Watch whether the strap stays in place or slides toward an uncomfortable spot. A narrow decorative strap can feel different from a broader one even when both look secure. Buckles, elastic sections, and hook-and-loop closures also offer different amounts of adjustment.
Keep the toe and heel in the comparison
A strap can disguise an otherwise loose shoe by preventing it from coming off. Check whether your foot still slides inside, whether the heel rubs, and whether the toes have suitable room. Security at one point does not establish a good fit throughout.
If the shoe has a heel, try it with the intended hosiery and take several ordinary steps. Foot position changes with the shoe's construction, so a Mary Jane flat and a heeled version may need separate fitting decisions. Do not transfer a size result automatically between them.
Operate the fastening yourself. Tiny buckles may be inconvenient if you remove shoes frequently, and an adjustable strap is useful only if you can manage it easily. Check that loose strap ends sit neatly rather than catching on a trouser hem.
Think about the outfit around the strap
An ankle-length trouser can leave the strap visible; a longer hem may catch on the buckle or hide the detail you liked. Tights and socks can change both the appearance and the amount of space beneath the strap. Try the complete combination before buying for a specific event.
A good Mary Jane uses its strap to refine a suitable fit. If the strap must work excessively hard to hold the foot in place, another shoe shape may offer a more comfortable solution.
