According to this Calorie Calculator Tool, a 30 min Swimming workout for 155 lbs or 70 kg exerciser can burn 350 calories. Note that each 5 min exercised will entail to additional burning calories.
How many calories are burned Swimming in other time-plans?
Other Swimming categories
Swimming is a really good for your overall health. However, other exercises findables in this Swimming section can improve flexibility, range of motion, strengthen muscles, build core strength and help you to burn more calories.