Men's swimwear like board shorts and swim trunks are similar in that they are both types of swimwear for men, but there are some differences. Board shorts are typically longer in length, often reaching the knee or below, and feature a loose fit. They are commonly worn for casual beach or surf activities. Swim trunks, on the other hand, are shorter and have a more fitted design, often featuring an elastic waistband. They are often preferred for swimming or recreational water activities.