This answer is a definitely YES! Over 70% of planet Earth is water of which 97% is ocean (salt water). With the amount of natural flood occurrences happening each year, not knowing how to swim can kill you. Keep in mind that glaciers and ice sheets are melting at a faster rate each year, and the sea level is rising. The likelihood of cities, towns and neighborhoods at low elevation will disappear over time (and the time is shorter than you think) is very high. Learning to swim is key, and you don’t need to necessarily swim fast, the ability to tread water and swim to an object to hang onto is good enough to survive and be rescued. Go learn today if you don’t know how to swim.