At a glance, it is diving without the use of an oxygen tank. This can be used for snorkelling, spearfishing or general fun. The sport of free-diving involves training for depth or time of breath retention, can involve a line, flippers, static breath holds, distances in swimming pool and more.
Having recently trained some freediving techniques with the Apnea Total schook, I fell in love with the activity and substantially increased the depth of my diving and time I could hold my breath underwater.
Highly recommended and an amazing way to enjoy the ocean. Please look at some clips on youtube to get inspired! about 5 years ago