At a casual glance, it might appear that men's swimsuits are far less varied than women's. After all, women can chose from one-pieces, bikinis, strapless, asymmetrical and a variety of other styles. Men, on the other hand, are usually confined to garments that cover only the lower portion of the body. (The notable exception to this rule is the new racing swimsuit, but more on that later.) However, even within those somewhat limiting parameters, men's swimsuits manage to exist in a reasonable number of variations. Some resemble biking shorts, while others look like the lower portion of a woman's bikini. While fashion and style are both a consideration, some swimmers also performance into consideration; some swimsuits are far more suited to competitive events, such as racing and diving, than others.

Trunks are the most ubiquitous style of men's swimsuit. They are loose, come to the middle of the thighs and are made of polyester or nylon. The only real difference between men's shorts and men's trunks is that the latter have polyester liners on the inside, which prevents them from becoming transparent when wet.

Men's boardshorts are one of the commonly worn styles of men's swimsuits. They are so named because of their traditional association with the sport of surfing. Boardshorts are fairly baggy and usually made from polyester or nylon. They are durable, lightweight and comfortable. These swimsuits are quite long in comparison to typical swim trunks, reaching to the knee or just slightly above. Tropical images, such as Hawaiian floral patterns, are popular on boardshorts.

Swim briefs, or "speedos," have been the uniform of male swimming racers and divers until very recently. These swimsuits leave very little to the imagination, being very formfitting and covering only the buttocks and groin area. Speedos have been used in competitive aquatic events because they create far less drag than a larger and baggier garment. The briefs are usually made of nylon or polyester and spandex, which results in a very tight material. As far as recreational use goes, the popularity of the speedo varies according to geographic location. While they are fairly rare in the United States, they are common in other countries, such as Brazil and France. It is also worth noting that swim briefs are the garment of choice for male body builders. The brevity of the brief allows these men to show off as much muscle mass as possible.

Recently, a new contender has emerged on the swimsuit scene for both men and women: the bodysuit. This item of clothing recently made history at the 2008 Olympic Games, where it contributed to the shattering of multiple swimming speed records. These suits cover the wearer from the neck to just above the knee, or sometimes down to the ankle. The material is lightweight and ultra thin, helping to streamline the wearer's shape. The swimmer's body is compressed in critical areas, which maintains optimal swimming posture and dampens muscle oscillation, making the racer's movements more efficient. These swimsuits also repel water, which further decreases the body's drag. Overall, the new racing suits are so efficient in improving the swimmer's speed that there was actually talk of banning them at the Beijing Olympics. Fortunately for Michael Phelps, this did not occur.