I just purchased two of these, in medium.   It isn't just that they "feel too big."  They are cut to fit someone about 5-9 weighing around 225 (or more) with an 18 inch neck.  I'm surprised Speedo would sell something like this.

This is a great tee to wear around everyone to rep your favorite brand and show your swimmer side.
the only drawback, however, is that they feel at leaast one size bigger than they're labled.