Men's Swimsuits: Some Things Never Change
Unlike women, most guys don't care THAT much about what they wear when swimming. I guess the one thing they DO care about the most is the amount of exposure their groin area has to avoid those embarrassing moments when the elements combine to create a hard-on. It happens without much warning and when it does, depending on the swimsuit, can be AWKWARD! Sure, the opposite sex no doubt notices and grins while trying not to stare. Other than that one item, most men consider length of the suit and pattern.
If the awkward moment occurs while in a bikini or brief swimsuit style (think Speedo), well, because of the material, it is nearly full exposure depending on the size and hardness. A quick dip into cold water will solve that! Using your towel also helps. Those swimsuits expose most of the man's body. Back 20+ years ago, men who wore them were stereotyped as being queer. Yeah, it was a stereotype.
Then, there are the long, baggy board suits that are excessive in length (think 1-2 inches BELOW the knee). Heck, you might as well long pants! I've have always hated those because they look ridiculous and take forever to dry. No thanks.
The short swimsuit, popular in the 60-70s, remain a decent choice. These suits are much shorter with the hem a good four inches above the knee, cut square, unlike the brief suit, which is similar to underwear in cut. The more popular are the suits I call "surfer suits". They usually have a hem about at the knee or 1-2" above it, which is a good length. They have tie strings in front with zipper-like seam. Most of these are made narrow in the leg to prevent ballooning when getting in the water. Another good suit for those with "love handles" in the gut area are suits with elastic waist bands. The elastic band will allow expansion and make your handles not appear to be that bad.
At the extreme end are swimsuits that simply barely cover the man's groin area with a small fabric cup and connected by a tie string. Like for women, any guy wearing these in public are simply doing for attraction. But since for both women and men, it is the body that makes the swimsuit look more appealing, this may not be a good thing.