A high instep and footies that slip off the heel

Short answer: Choose a footie with a higher back cut and silicone in the heel. A high instep pulls the sock forward with every step, no matter how well it otherwise fits the foot.

What happens

A high instep makes the distance from heel to instep longer than on an average foot. A footie cut for a flat instep gets stretched backward as a result and slips down over the heel. This repeats with every step until the sock ends up sitting inside the shoe instead of on the foot.

The back cut decides it

Look for models where the back piece runs higher and covers the whole heel, not just the tip of it. A low back cut is designed for a flat instep and rarely works on a high one, whatever the material. See bamboo footies for women.

Silicone does the rest

A silicone strip or dot on the inside of the heel creates friction against the skin, where the fabric would otherwise slide freely. It is the single trick that works best against slipping, and it usually adds only a small amount to the price. See bamboo footies for men.

The alternative is an ankle sock

If footies keep slipping even with the right details, a low ankle sock is the safe solution. It barely shows in a low shoe and stays in place all day, whatever the height of the instep. See bamboo socks for women.

The stretch of the fabric matters too

A fabric with plenty of elastane follows the foot's movement better and holds the heel better than a stiff, inelastic fabric. Combine good elastane with a high back cut for the best result on a high instep.

How to test the footie at home

Take a few steps on a hard floor with your shoes on and feel whether the sock shifts inside the shoe. If it slips after only a few steps, the problem will only get worse over a full day out.

The shape of the shoe matters too

A shoe with a low back edge gives the footie less to hold onto. In that kind of shoe, a high back cut and silicone matter even more, while a shoe with a higher back edge is more forgiving of a simpler footie.

Keep track of pairs that slip

If you notice that only one pair of footies keeps slipping, it is usually the model and not your foot that is the cause. Replace that model rather than living with the problem every day.