These socks are one size fits most and are suitable for ages 6 - 99. They can fit adults but we recommend up to shoe size EU 41 equivalent to women's size 8/9 AU. Please note, that they do have limited stretch around larger or muscular calves. Socks with less busy patterns such as (Mermaid Socks, Liquorice Bows Socks, Bows to Toes Socks) have better stretch and we highly recommend these patterns for adults to avoid stretch issues Size: Kids And Adults (6+)