Slowbro is a bulky and reliable choice for many teams in UU with his ability to check a large portion of the physical sweepers in the tier. He can fit well into frail, offensive teams in need of a little insurance against the likes of Azumarill and Fighting-types, while also providing useful paralysis support and doing reasonable amounts of damage with his own attacks. Slowbro's low Speed is made up for by his good defenses, and this also makes him one of the most reliable users of Trick Room in the game. While commonly seen only as a defensive threat, Slowbro can also very quickly go onto the offensive with Calm Mind or Choice Specs, making the most of his respectable Special Attack and wide movepool.
Slowbro is one of the physically bulkiest Water-types in the game, and his useful resistances to Fighting, Water, and Fire allow him to check a lot of UU's biggest threats. Instant recovery in the form of Slack Off means he has incredible staying power against physical sweepers, and his Psychic typing and ability to reliably spread paralysis with Thunder Wave set him firmly apart from other bulky Water-types such as Milotic. The combination of 95 base HP and 110 base Defense is very hard to break with neutral attacks, and when instant recovery is thrown on top of it, physical sweepers will struggle even more to bypass Slowbro. He brings a whole host of very threatening Pokemon, including Azumarill, Hariyama, Feraligatr, Hitmonlee, Hitmontop, Poliwrath, and Arcanine, to a grinding halt.Team Options & Additional Comments >>>
While Slowbro usually plays the role of a passive, defensive bulky Water-type, Calm Mind provides a way for him to gradually become a very real offensive threat, while at the same time patching up Slowbro's less than stellar Special Defense. With access to Slack Off for instant recovery and good coverage with his STAB attacks, Slowbro makes for a reliable and powerful tank after a few boosts.Team Options & Additional Comments >>>
Slowbro and Slowking share a lot of things in common, and one of these is the ability to set up Trick Room. When opting for one of them on a Trick Room team, it is important to choose the right one for your team's needs, as both do a slightly different job well. There is little use trying to use Slowbro to both set up Trick Room and sweep during it, since Slowking has access to Nasty Plot, which allows him to become a threat much faster than Slowbro can with Calm Mind. Conversely, Slowbro is usually the preferable choice for a super bulky Trick Room supporter, as Slowbro's higher Defense stat makes the most of his resistances to common physical Fighting and Water attacks and allows him to do the job slightly better than his sibling.Team Options & Additional Comments >>>
Slowbro's biggest advantages over other more powerful Specs users is his ability to cripple Chansey and other special walls with a Tricked Choice Specs, and the surprise value involved when a cute, defensive hermit crab hits with enough power to 2HKO Clefable. That, and Slowbro's considerable bulk even with just HP investment making up for its abysmal Speed, make Slowbro a slow but powerful Choice Specs tank.Team Options & Additional Comments >>>
Slowbro has a very wide movepool for a bulky Water, but unfortunately most of it is of little use. In addition to Surf, Psychic, Ice Beam, and Grass Knot, Slowbro can use Flamethrower, Fire Blast, Shadow Ball, Focus Blast, and Signal Beam. The Fire moves' only target in UU that isn't hit as hard by Ice Beam or Slowbro's STABs is Registeel, and it poses a minimal threat to Slowbro because Registeel has a low Attack stat and no form of recovery bar Rest. All the other moves have no notable targets that aren't hit suitably as hard by one of Slowbro's STABs.
There are also several viable support moves that Slowbro can use and could be helpful depending on your team's needs. Yawn can cause a lot of switches, and Slowbro has the bulk to use it effectively. Counter is an interesting choice against Pokemon such as Scyther and Drapion, who will try to overpower Slowbro on the physical side with super effective moves, but it is quite unreliable as most players tend to prey on Slowbro's weaker Special Defense. Curse is quite a gimmicky option, and is better left to Slowking anyway, as his superior Special Defense allows him to pull it off more effectively.
With Slowbro receiving physical Water STAB in the form of Aqua Tail from Platinum move tutors, a set utilizing Trick Room, Belly Drum, Aqua Tail and Zen Headbutt could be attempted. A Sitrus Berry is a good idea as it effectively halves the cost of using Belly Drum and is more beneficial for the make or break type of sweep Slowbro attempts with this strategy as compared to Leftovers' more consistent recovery. Slowbro's other physical attacks include Earthquake and Drain Punch, the latter of which might still be viable alongside Aqua Tail, especially if a Chansey comes in expecting a Surf as you Belly Drum. However, the entire strategy is very risky and situational, and so should not be relied on.
Putting 252 EVs into Slowbro's HP should be the first step for almost all the sets, since it maximizes his overall bulkiness. Then the remainder of the EVs should be allocated into Defense for the more tankish sets, and Special Attack for the Specs set. Investing significantly in Special Defense is generally fruitless, as it detracts from Slowbro's physical hit-taking ability too much and because Milotic or Slowking perform better at special walling. For example, the standard Blaziken's Fire Blast followed by a Hidden Power Grass will beat Slowbro after Stealth Rock damage. Guaranteeing survival against this, taking into account the damage Slowbro sustains from Stealth Rock upon entry, would require you to run almost max Special Defense alongside max HP, at which point you're just better off using Slowking or Milotic.
Running max HP and max Defense allows Slowbro to survive quite a few super effective physical attacks - with this investment, a max health Slowbro is guaranteed to never be OHKOed by a Choice Band Rhyperior's Megahorn, letting Slowbro retaliate with a last-ditch Surf. Reducing the HP stat down to 212 EVs and using a Leftovers number is not recommended, as it detracts from Slowbro's overall bulkiness, and the difference in Leftovers gain is insignificant when taking into account Stealth Rock.
If you are particularly worried about Spiritomb, 44 Speed EVs allow Slowbro to outspeed minimum Speed versions. However, this is rarely a worthwhile investment because it is solely for Spiritomb, and Slowbro won't really be beating the ghost even if he is faster.
Checks and Counters
Venusaur can come in on Surf, Toxic, or Slack Off and pose an immediate threat to Slowbro with his powerful STAB Grass attacks. Sceptile fares similarly, and while it isn't quite as specially bulky as Venusaur, neither is it weak to Psychic. Torterra is immune to Thunder Wave, isn't hit super effectively by either of Slowbro's STABs, and has a high chance to OHKO with a Life Orb-boosted Wood Hammer after Stealth Rock. Ludicolo packs a 4x resistance to Surf and has a high Special Defense for taking Psychics as well. With his Grass STAB, he can use Energy Ball or Grass Knot to quickly dispose of Slowbro. Chansey and Clefable are both undaunted by status, Chansey because of Natural Cure and Clefable because of Magic Guard and her tendency to hold Toxic Orb. Both have very high Special Defense and threaten Slowbro with Toxics of their own. If Slowbro is carrying Thunder Wave over Toxic, Lanturn can come in without much trouble and threaten with a super effective STAB Thunderbolt.
Spiritomb doesn't mind Toxic unduly since he often carries Rest, and threatens to come in on his Psychic immunity. Calm Mind versions are particularly dangerous to Slowbro as Spiritomb has 5 higher base Speed, and so can Calm Mind up to take less and less damage from Surf before he hits back with his own STAB super effective Dark Pulse. As long as Mismagius avoids Thunder Wave, she can take a weak hit with her base 105 Special Defense and OHKO Slowbro with Shadow Ball. Specially defensive Drapion can come in on a Psychic, prevent Slowbro from healing or statusing Drapion with Taunt, and then Swords Dance up and beat Slowbro with Crunch. Curse Registeel also sees Slowbro as nothing but setup fodder.