Make a swimmable mermaid tail in three easy steps. You'll need pattern paper, swim fabric and elastic, and a monofin.
Step 1: Trace the Pattern
Trace around the lower body from belly button level to toe tips. Use any paper large enough such as pattern paper, postal paper, or a cut-open paper bag.
Line up the monofin with the toe area and trace to complete the pattern.
Add 1 inch allowance around the trace line for a child or 2+ inches for an adult.