Battle Moveset

A Good Moveset for Sharpedo would have to be this:

Attacks:

Earthquake
Hidden Power [Flying]
Substitute
Hydro Pump / Ice Beam

Items Attached:

Liechi Berry

Preferred Nature:

Hasty

Strategy Using Sharpedo

Sharpedo has no defences so offence is the only way to go with it. It's blessed with a great attack and good special attack stat as well as a good speed stat, giving it a lot of potential in the underused environment as a mixed sweeper. It's best shot at a successful sweep is late game when most of your opponents team is weakened to the point that Sharpedo can KO it's opponents in one hit. Substitute until the Liechi Berry is activated and then sweep. Earthquake is a staple move and covers any potential electric typed switch-ins while Hidden Power [Flying] can cover Grass types. Hydro Pump gains STAB and does large amounts of damage without any EV support while Ice beam can catch Flying types switching in to block Earthquake.

EV Corner:

EVs: 252 Atk / 252 Spd / 6 SAtk
Hasty Nature (+Spd, -Def)

Since the only attacks Sharpedo has a remote chance of surviving are its resistances, of which most are based off of special offence, sacrificing Defence with a Hasty nature is best suited for Sharpedo. When setting the Hidden Power opt for the 30/30/30/31/30/30 settings so that Speed isn't sacrificed, allowing a tie in speed with other Pokémon with Max Speed from the Base Speed 95 category.

Other Optional Sets:

Sharpedo @ Petaya Berry
Trait: Rough Skin
EVs: 252 Spd / 252 SAtk / 6 SDef
Timid Nature (+Spd, -Atk)
- Crunch
- Surf
- Substitute
- Ice Beam

Special Sweeper Sharpedo. Double-STAB and a versatile move give this set some potential. It follows a similar strategy to the physical sweeper, Substitute until the Berry is activated and then sweep.

Sharpedo @ Choice Band
Trait: Rough Skin
EVs: 252 Atk / 252 Spd / 6 SAtk
Lonely Nature (+Atk, -Def)
- Earthquake
- Hidden Power [Flying]
- Double-Edge
- Hydro Pump / Ice Beam

There are much better UU Choice-Band Pokémon but CB Sharpedo has potential. Since it isn't sweeping but rather using a Hit-and-Run method it can sacrifice a +Speed Nature for a +Attack nature, allowing it to pack a much larger punch than the physical sweeper. A poor physical move pool lets it down however, mostly forcing it to rely on Hidden Power and Earthquake with Double-Edge as an option for power while having a special attack as a supporting move for any strong physical walls that won't take a huge hit from it's physical attacks.

Other Optional Moves

Endure, Screech, Roar, Taunt, Torment, Crunch. Endure is an option over Substitute and is a unique method for countering Reversal/Flail Pokémon when teamed with it's 'Rough Skin' trait. Screech and Roar can force switches and has some potential teamed with Spikes, Screech more-so since it teams nicely with it's good attack trait but is blocked by Clear Body (and White Smoke but Torkoal would be crazy to switch into Sharpedo). Taunt is a cool move when timed properly and gels nicely with Sharpedo's great speed stat but Sharpedo's defences are too poor to risk it on the standard sets, same goes for Torment. Crunch is an option on the physical sets but will pale in comparison to Hydro Pump in most situations.

Strategy Against Sharpedo

Sharpedo's defences are poor and even attacks that are resisted should take a fair chunk out of it. What Sharpedo can't kill it'll probably run from. Faster sweepers especially but also some of the bulkier tank Pokémon that it can't 1KO. Trying to hit it with statuses is usually a bad idea since Substitute is a staple on Sharpedo but if you can predict correctly then a Thunder Wave will usually be enough to shut down Sharpedo for the rest of the battle.

Contest Moveset

A good Contest Moveset for Sharpedo would have to be this for the Tough Contest best with Impish, Lax, Relaxed or Bold Nature:

Attacks:

Crunch
Rain Dance
Surf
Thrash

Items Attached:

Yellow Scarf

Strategy Using Sharpedo

If you do the attacks in this following order you should have very few problems; 1st - Crunch, 2nd - Rain dance, 3rd - Surf, 4th - Crunch 5th - Thrash

Locations in Games

Ruby/Sapphire/Emerald Routes 103, 118, 122, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, Mossdeep City, Pacifidlog Town (Fish) Colosseum/XD Trade from RSE Fire Red/Leaf Green Trade from RSE

Animé Appearences

Sharpedo has had a couple of Animé Appearences. First it was present just Ash made it to Hoenn. After that, Ash & Co. get stranded aon an island between Rustboro & Dewford after being attacked by School of Sharpedo Episode 276: Hoenn Alone! Episode 295: Sharpedo Attack!