Kingdra's stats may make it seem like it's outclassed by Dragon-types such as Palkia and Rayquaza. However, Kingdra's ability, Swift Swim, puts it in a class of its own. With Kyogre's eternal rain, Kingdra becomes an excellent revenge killer, and either a powerful mixed attacker, or a sweeper that is incredibly difficult to revenge kill. In the rain, Kingdra will outspeed even Choice Scarf Garchomp and Choice Scarf Palkia, and will easily OHKO both with its powerful, STAB Dragon-type attacks. No other Dragon-type is capable of doing this in Ubers, often making Kingdra a deadly surprise for most teams that rely on Choice Scarfed Dragon-type Pokemon to stop sweeps from Rayquaza. Overall, Kingdra is an excellent Pokemon in Ubers, and is the prime candidate to base an Uber rain team around.
While Kingdra may seem like it's outclassed by Rayquaza, Dragon Dance Kingdra has two very significant advantages over Dragon Dance Rayquaza in Ubers. First of all, Kingdra's typing grants it a neutrality to Ice-type attacks, Stealth Rock, and a resistance to Bullet Punch. Most importantly, the quality that truly makes Kingdra stand out in Ubers is Swift Swim. With only 176 Speed EVs and Kyogre's eternal rain, Kingdra is able to outspeed Choice Scarf Garchomp, the fastest Dragon-type Pokemon commonly seen in Ubers. After a Dragon Dance, Kingdra will easily outspeed every single Pokemon in the Uber metagame.
Waterfall is Kingdra's main STAB attack, which, thanks to Kyogre's rain, becomes just as powerful as Outrage. Outrage complements Waterfall extremely well, allowing Kingdra to have nearly perfect type coverage (with only Shedinja not being hit at least neutrally). Even before a Dragon Dance, Waterfall is a useful move for revenge killing several threats simply because this Kingdra has a Speed stat of 500 in the rain. For instance, Darkrai has around a 92% chance of being OHKOed by an unboosted Waterfall after it takes Stealth Rock damage. While Kingdra is not as powerful as Rayquaza, its boosted Waterfalls and Outrages will still deal a massive amount of damage. For example, a +1 Outrage will always OHKO max HP Kyogre after it takes Stealth Rock damage, while a +1 Waterfall in the rain or Outrage will easily OHKO Mewtwo. The last slot is best occupied by Draco Meteor for two reasons: Draco Meteor will deal over 50% to most Groudon and Dialga switch-ins (barring specially defensive Dialga), meaning that next time Kingdra gets time to set up, Groudon will often be unable to switch in and take control of the weather without sacrificing itself, and Dialga that are not specially defensive will often be KOed by Outrage after being hit by Draco Meteor. Draco Meteor will also have enough power to OHKO Rayquaza, Garchomp, and Palkia, meaning that Kingdra can destroy them without getting locked into Outrage. Yawn is a reasonable option in the last slot if Groudon is not a problem for your team. Yawn can potentially put your opponent's Kingdra check to sleep, or cause a switch that Kingdra can take advantage of by using Dragon Dance. When using Yawn over Draco Meteor, use an Adamant nature and relocate the 80 Special Attack EVs, because Kingdra will no longer be a mixed attacker.Team Options & Additional Comments >>>
Thanks to Kingdra's Speed in the rain and Life Orb, Kingdra can easily become a powerful mixed attacker and revenge killer in one set. The most important choice to make is between using Surf or Hydro Pump. Surf is weaker than Hydro Pump, but the perfect accuracy often makes up for the power loss. In the rain, Surf will still do a massive amount of damage to any Pokemon who does not resist it. For example, Surf will OHKO Darkrai, while both Lugia and Calm Wobbuffet are 2HKOed when taking Stealth Rock damage and Leftovers recovery into account. Hydro Pump trades the reliable 100% accuracy for more power, which can be helpful in certain situations. For instance, offensive Mewtwo is always OHKOed by Hydro Pump (compared to Surf's approximately 66% chance of achieving the same after Stealth Rock damage), and will also always 2HKO Lugia regardless of any entry hazards. Hydro Pump has a chance of putting specially defensive Groudon into the KO range of Draco Meteor after it takes Stealth Rock damage; something that Surf can never do. Aside from its poor accuracy, Hydro Pump also only has 8PP, meaning that it will run out fast in a metagame infested with such a high number of Pokemon with Pressure. Because of these setbacks, make sure you only use Hydro Pump over Surf if your team needs it.
Draco Meteor is Kingdra's most powerful attack against Pokemon who resist its STAB Water-type attacks, and will do almost as much damage as Surf in the rain! Draco Meteor will always OHKO every Dragon-type Pokemon who is weak to it with the exceptions of Giratina (who is OHKOed after taking Stealth Rock damage unless it is specially defensive), and Latias. Draco Meteor will also 2HKO most Groudon switch-ins after Stealth Rock damage, allowing your team to effectively take control of the weather. While Outrage may not pack as much of a punch as it did on the Dragon Dance set, it is still able to OHKO Latias, 2HKO Blissey, and 2HKO max HP Kyogre after it takes Stealth Rock damage. Finally, Waterfall's main purpose is to 2HKO Blissey in the rain, and to always 2HKO Tyranitar.Team Options & Additional Comments >>>
Kingdra is capable of using a Choice Specs set in Ubers, which in conjunction with Swift Swim, can deal a huge amount of damage. However, it lacks the sweeping and/or the wallbreaking capabilities the other sets possess due to being restricted by a Choice item. A Choice Band set may be tempting with Waterfall and Outrage, but Kingda's physical move pool is too poor to support such a set. Substitute can be used on any of Kingdra's sets to scout out potential counters and to protect against status, however Kingdra's health will be drained fast if used with Life Orb.
Dragon Pulse can be used as a more reliable special Dragon-type attack alongside Draco Meteor if needed. If using Dragon Pulse, make sure you use max Special Attack and a +Special Attack nature, as this will ensure that you will not only OHKO Rayquaza and Garchomp, but also OHKO Palkia after it takes Stealth Rock damage. Toxic can be used to cripple Lugia and Groudon switch-ins. Ice Beam can be used to 2HKO Groudon, but otherwise Draco Meteor is always the better move.
Checks and Counters
Because of Kingdra's Dragon-typing and Speed in the rain, it is extremely difficult to counter in the Uber metagame. A Dialga with max HP, max Special Defense, and a Careful nature is the closest thing to a true Kingdra counter in Ubers. All other Dialga variants will have difficulty switching in, but they will be able to revenge kill Kingdra due to almost never being OHKOed by Kingdra's assaults. Although Choice Scarf Rayquaza cannot switch into Kingdra, it can easily revenge kill it thanks to Air Lock. Specially defensive Groudon will be able to take most of Kingdra's attacks thanks to the sunlight and cripple Kingdra with Thunder Wave. Groudon's sun will make Kingdra much easier to deal with by the rest of your team as well, as Kingdra loses its Speed boost and is walled by common Steel-types such as Scizor.
While Kingdra is extremely difficult to revenge kill in the rain, there is a tactic that can be employed to defeat it. Since Kingdra is forced to KO Dragon-type Pokemon with Outrage if it has used Draco Meteor once, a good way to defeat Kingdra is to lure it into Outrage. When lured into Outrage, powerful, Steel-type attackers such as Scizor and Metagross can deal a severe amount of damage to it with their physical attacks. Jirachi in particular can use this time to paralyze Kingdra with Thunder Wave.