Spearfishing is an ancient method of fishing that has been used throughout the world for millennia. Early civilizations were familiar with the custom of spearing fish from rivers and streams using sharpened sticks.

Spearfishing today employs modern and more effective elastic or pneumatic powered spearguns and slings to strike the hunted fish.

Spearfishing may be done using free-diving, snorkeling, or scuba diving techniques. Because of a view that there is a lack of sportsmanship in some modern spearfishing techniques, the use of mechanically powered spearguns is outlawed in some jurisdictions.

Spearfishing is highly selective, with a low amount of unintended by-catch. With education and proper regulations, spearfishing can be an ecologically sustainable form of fishing.

The best free-diving spear fishers can hold their breath for 2 to 4 minutes, and dive to depths of 40 or even 60 meters (130 to 200 feet). However, dives of about one minute and 15 or 20 meters (50 to 70 feet) are more typical for the average spear fisher.

Spearfishing with barbed poles (harpoons) was widespread in palaeolithic times.Cosquer cave in Southern France contains cave art over 16,000 years old, including drawings of seals which appear to have been harpooned.

There are references to fishing with spears in ancient literature; though, in most cases, the descriptions do not go into detail. An early example from the Bible in Job 41:7 : Canst thou fill his skin with barbed irons? or his head with fish spears?.

The Greek historian Polybius (ca 203 BC–120 BC), in his Histories, describes hunting for swordfish by using a harpoon with a barbed and detachable head.

Oppian of Corycus, a Greek author wrote a major treatise on sea fishing, the Halieulica or Halieutika, composed between 177 and 180. This is the earliest such work to have survived intact to the modern day. Oppian describes various means of fishing including the use of spears and tridents.

In a parody of fishing, a type of gladiator called retiarius was armed with a trident and a casting-net. He would fight against the murmillo, who carried a short sword and a helmet with the image of a fish on the front.

Copper harpoons were known to the seafaring Harappans well into antiquity. Early hunters in India include the Mincopie people, aboriginal inhabitants of India's Andaman and Nicobar islands, who have used harpoons with long cords for fishing since early times.

In the 1920s, sport spearfishing without breathing apparatus became popular on the Mediterranean coast of France and Italy. At first, divers used no more aid than ordinary watertight swimming goggles, but it led to development of the modern diving mask, swimfin and snorkel. Modern scuba diving had its genesis in the systematic use of rebreathers for diving by Italian sport spearfishers during the 1930s. This practice came to the attention of the Italian Navy, which developed its frogman unit, which affected World War II.

During the 1960s, attempts were made to have spearfishing recognized as an Olympic sport. This didn't happen. Instead, two organisations, the International Underwater Spearfishing Association (IUSA) and the International Bluewater Spearfishing Records Committee (IBSRC), maintain lists of world records by species and offer rules to ensure that any world record setting fish is caught under fair conditions. Spearfishing is illegal in many bodies of water, and some locations only allow spearfishing during certain seasons.

In 2007, the Australian Bluewater Freediving Classic became the first spearfishing tournament in the world to be accredited and was awarded 4 out of 5 stars based on environmental, social, safety and economic indicators.