With a superb base 135 Special Attack stat, an excellent Speed stat, and potent coverage with its dual STABs, it's hard to see why Volcarona isn't a top-tier threat. However, when thinking of Volcarona's drawbacks, look no further than its typing. While great offensively, Fire- and Bug-types make a poor defensive combination, cursing Volcarona with weaknesses to common spread moves, such as Rock Slide and Surf. It also needs a little team support to get going, as it can otherwise be a sitting duck against sand and rain teams. However, Volcarona's ability to dent and KO common Pokemon, such as Cresselia and Metagross, along with miscellaneous Trick Room users, is valuable in a fast-paced metagame.
This set aims to use Volcarona's great coverage and awesome offensive stats to their maximum potential. Heat Wave and Bug Buzz are two potent STAB moves, allowing Volcarona to hit multiple Pokemon at once and leave large dents in Psychic-types, respectively. The move used in the third slot depends largely on what you want Volcarona to be able to defeat. Hidden Power Ice is the most useful move, as it can destroy the common Dragon-types that normally wall Volcarona, such as Salamence and Dragonite. Hidden Power Ground decimates Heatran, who otherwise walls Volcarona, and powers through opposing Fire-types, such as Chandelure and Arcanine. Rage Powder might seem like an odd move to use on such a frail Pokemon, but it allows Volcarona to redirect priority moves, such as Bullet Punch and Mach Punch, possibly burning the offender thanks to Flame Body. Focus Sash and Protect act as safety nets, ensuring Volcarona isn't taken out too early by a surprise Rock Slide.Team Options & Additional Comments >>>
Volcarona's movepool includes many other Fire-type STAB moves, namely Fire Blast, Flamethrower, and Fiery Dance. While these moves cannot hit two opponents at once, they can be used for the boost in power they provide compared to Heat Wave. SolarBeam is an interesting option on a sun team, but most of SolarBeam's targets will be found on sand and rain teams, which reduces its effectiveness. Hurricane is an interesting option; it allows Volcarona to perform in or against rain teams, and also has an added chance of confusing the opponent. However, Hurricane's accuracy receives a huge drop in sunlight, while rain weakens Volcarona's Fire-type STAB moves, making the two incompatible. Psychic can reliably defeat Fighting-types, which usually carry Rock-type moves. Volcarona is one of the select few Pokemon that can viably use stat-boosting moves in VGC 2012, making Quiver Dance an attractive option. While using Quiver Dance requires more team support than usual, it can prove extremely potent if used correctly.
Volcarona also receives solid support options besides the listed Rage Powder, such as Safeguard and Sunny Day. Though these could probably be used to better effect on bulkier Pokemon, they allow Volcarona to become a little more independent, protecting itself from negative effects, such as rain and paralysis. Fire and Bug Gems help Volcarona score OHKOs on certain Pokemon, such as Zapdos and Tyranitar. However, Focus Sash is too good of an item for Volcarona to pass up, so Gems should be used only if you are in desperate need of them. Hidden Power Rock hits both Fire- and Dragon-types that give Volcarona headaches, though it lacks the power to reliably defeat Dragon-types, and also requires a different EV spread. If you're not concerned about Water-type moves and have another Pokemon in need of a Focus Sash, Charti Berry will protect Volcarona from at least one Rock Slide, provided Volcarona is in good condition.
Checks and Counters
In general, Pokemon that can use Rock Slide and either take a hit from or outspeed Volcarona are instantly threats. Tyranitar can effectively strip Volcarona of its Focus Sash, though it's better off not going up against Volcarona directly due to Bug Buzz. Terrakion can outspeed and OHKO most Volcarona, or at least knock it down to its Focus Sash with Rock Slide. Heatran, though relatively uncommon, walls all Volcarona that lack Hidden Power Ground. Gyarados will also wall Volcarona, and can easily KO it with Waterfall or Rock Slide, or paralyze Volcarona to make it dead weight; Salamence and Dragonite similarly take little damage and can prey on its low Defense by nailing it with Rock-type moves. Trick Room is a large thorn in any fast and frail attacker's side, and Volcarona is no exception. However, common Trick Room leads will not enjoy taking Volcarona's STAB moves, and Fake Out users run the risk of getting burned by Flame Body. On rain teams, Swift Swim Pokemon such as Kabutops and Kingdra can douse Volcarona before it can move.
Volcarona receives Swarm from the Dream World. As Volcarona usually holds a Focus Sash, it can take advantage of this ability with Bug Buzz. However, some crucial Pokemon that Bug Buzz needs to KO, such as specially defensive Cresselia, cannot be KOed even after a Swarm boost. So unless you are feeling lucky, stick with Flame Body.