Sockliner Explained

In brief: The sockliner is the removable foam insole inside a running shoe that sits directly under your foot, adding a layer of cushioning and shaping the footbed.

What is the sockliner?

The sockliner, also called the insole or footbed, is the thin removable layer of foam your foot rests on inside the shoe. It sits on top of the midsole. While it adds only a little cushioning, it shapes the immediate feel underfoot and can usually be lifted out and replaced.

What it does

The sockliner provides a soft top layer, helps wick moisture and gives the footbed its contour, including any arch shaping or heel cup. Because it is removable, it lets runners swap in custom orthotics or aftermarket insoles. It also affects volume: removing a thick sockliner frees up room for a higher-volume foot or an orthotic.

Types and variations

Most sockliners are moulded EVA foam. Some premium shoes use higher-rebound foams or add extra arch and heel shaping. Ortholite and similar branded foams add breathability and anti-odour properties. Flat sockliners suit those who use their own insoles; contoured ones add built-in support.

What to look for

If you use orthotics, check the sockliner is removable and the shoe has room once it is out. If you want more cushioning or arch support, an aftermarket insole can transform a shoe. A worn, flattened sockliner is cheap to replace and can refresh an otherwise good shoe.

The sockliner and your running kit at OD's

Swapping a sockliner or insole is one of the easiest ways to fine-tune fit and feel. We are happy to advise, with next-day delivery and free click and collect.