Cut the swimsuit liner out.

Yes — the easiest fix is to just remove the liner with scissors. It’s not structural.

Most swimsuit liners are cheap mesh sewn in at the seam. They bunch because they’re too thin to stay put. If your suit has any kind of lining already — or if the fabric itself is thick enough — you don’t need that inner layer. Snip the stitches with small scissors, pull the liner out, and done. No more wedgie, no more visible edges.

If the suit is completely unlined (like a thin white or light color), you might need to keep it. In that case, sew the liner down at a few points with a needle and thread — just tack it to the inner seam. That stops it from migrating. But honestly, most people can just cut it.

Future you will thank you at the beach.