Some ocean swim events may require the wearing of a lycra swimming vest for safety or sponsorship purposes.
Wearing a swim vest for the first time may feel restrictive, and you might feel a little more resistance when you swim.
Choosing and fitting a swimming vest
When choosing a vest size always ask for a size or two smaller than you would usually wear so it fits nice a snug.
If you still need to tighten it try gathering the loose material together and tying a knot in the back.