When ever Poseidon was angry or mad, he would always strike the ground with his trident which would cause shipwrecks, drownings, tsunamis, and earthquakes(after all he was also the god of earthquakes).
To protect the ocean
To demonstrate his sovereignity over land and water since when the three brothers [Hades - Zeus and Poseidon] defined the areas of responsibility the surface of earth was given to Poseidon. With his trident [Τρίαινα] he was creating the earthquake and the waves of the oceans and seas.
what are three reasons to carry it.
In the Titan War, in which Hades, Poseidon, and Zeus overthrew their father Cronus, the Cyclops who had been imprisoned within Gaia were released and they gifted the three gods with the following; Zeus his thunderbolt, Poseidon with his storm-raising trident, and Hades with a helm of invisibility.
After defeating their father, the big three(Zeus, Hades, and Poesidon), the cyclops gave them special gifts for freeing them. Zeus got his bolt, Hades got his helmet of invisability, and Poesidon got his trident
The Symbol was created for Poseidon because he was determined to be the god of water, strength and horses. He created water with the Trident.
Fishermen in Greece used tridents to fish so it made sense for the God of the Sea to have a trident.
however you are you sure ask a lot of question's, every god has a lot of power and they can't store inside so they store half of it there weapon does that answer your question.
He used it to make earthquakes floods...
His Trident.
Poseidon's trident is one of his most iconic symbols.
The trident
Trident
Poseidon's uncle the Cyclops gave poseidon his trident.
Poseidon fought with a trident, a three-pointed spear.
Poseidon have a trident that can shake the earth and any object.
Poseidon's trident was made by the cyclopes
Trident is the son of Poseidon
Well Poseidon got his tridentafter hephaestus made Poseidon's Trident
Poseidon is usually shown carrying a trident.
Poseidon has a trident