Medium is 64 stitches around in gauge.
Large is 72 stitches around in gauge.

Sock yarn recommended.

Pattern is written for magic loop method, but small circulars or double pointed needles work great as well. Simply divide the front and back stitches evenly.

This is an intermediate pattern, so it assumes some knitting knowledge on your part, but beginners are encouraged to join in knitting up cute mermaid-inspired socks!