When I was at Target a few weeks ago, I saw a whole bunch of adorable striped bikini bottoms, so I snagged a couple that were on sale. The only problem is that they have the open ties on the sides. And since I'm not really confident in my knot tying skills, and have no desire to literally lose my shorts at the waterpark, I did a quick alteration and sewed up the sides.
Here's what they looked like before:
*I bought a size up from my normal size since I was taking in each side about an inch*
Step 1. Pull out the side ties...
...and line up the two sides. Pin if you want (I didn't).
Step 2. With a thread that won't stand out too much (I used white), do a very close zigzag stitch, zigzagging on and off each side.
And that's it! You're done!
The stripes on mine didn't match up, but when the swimsuit is on, it doesn't bother me at all.
If desired, sew the ties back on for a decorative bow on each side (I didn't).