Vaporeon

Vaporeon, The Bubble Jet Pokémon.

Its cell composition is similar to water molecules. As a result, it can melt away into water. It has evolved to be suitable for an aquatic life. It can invisibly melt away into water. It prefers beautiful shores. With cells similar to water molecules, it could melt in water. When its fins begin to vibrate, it is a sign that rain will come within a few hours
Overview

Vaporeon used to be the undisputed best Eeveelution, but since Espeon got access to the incredible Magic Bounce, Vaporeon has lost the title of best. Not to say it is bad, it's still great! Just... not the best Eeveelution. Dream World brought it a new way to heal in Hydration and Rest, which is basically a free full heal in rain. Otherwise, Vaporeon hasn't changed much at all. It still uses the old standard of Wish/Protect/Water move/filler, and does it quite effectively. Vaporeon hasn't gotten worse, but it has some new bulky Waters to compete with, and has only slightly improved. It's a great Pokémon though, that can even go on the offensive with a great base 110 Special Attack.

Abilities
Water Absorb: awesome ability. It can be an autowin against something like ResTalkDDGyarados or whatever. At worst, it's a free switch in into any Water move, and you get HP back.
Hydration: only use this on a Drizzle team. Combined with Rest and rain, you have a full heal move with no drawbacks (unless of course rain is removed from play). Great ability now Drizzle Politoed exists.
Hydrate your senses
- Rest
- Scald
- Ice Beam / Hidden Power [Electric]
- Roar / Toxic
Item Attached: Leftovers
Ability: Hydration
EVs and Nature:
EVs: 252 HP / 252 Def / 4 SDef
Bold Nature (+Def, -Atk)
Rest makes you practically immune to status... well, no, not immune, you just don't care about status at all. In rain, Rest heals you to max and Hydration wipes out any status effects you have including the Sleep from Rest. Scald is a new move that is a really great choice for a Water move on pretty much any Pokémon. It's the only Water move that can burn, which is amazing. Ice Beam gets great coverage with Scald, and is a boss attack in general. Hidden Power [Electric] is an alternative if you want to lay out stuff like Gyarados. Roar phazes, which is always good for more entry hazard damage. Toxic allows you to stall stuff out with Rest spam.
Is that an airplane in the night sky?
- Wish
- Protect
- Scald
- Roar / Toxic / Ice Beam
Item Attached: Leftovers
Ability: Water Absorb
EVs and Nature:
EVs: 252 HP / 252 Def / 4 SDef
Bold Nature (+Def, -Atk)
Thought it was a shooting star... anyway, Wish got buffed... nerfed... well, it depends how you look at it. Wish now heals 50% of the user's HP, regardless of whether you switch to another Pokémon. So, for example... Vaporeon with max HP uses Wish, it will heal whatever you switch to for 232 HP, which for offensive Pokémon if often most of their health. It makes Wish worse for other Pokémon, but for high HP users it works well. Protect stalls for the turn Wish takes to work, wastes their PP, and stalls for any status damage. Scald can burn, which is awesome, and it is still fairly strong. Roar phazes and scouts, Toxic inflicts a crippling status on stuff and allows you t stall them out,Ice Beam combos well with Scald.
Specsporeon
- Surf / Hydro Pump
- Ice Beam
- Hidden Power [Electric] / Hidden Power [Fire]
- Baton Pass / Shadow Ball
Item Attached: Choice Specs
Ability: Water Absorb
EVs and Nature:
EVs: 252 HP / 4 Def / 252 SAtk or 4 HP / 252 Def / 252 SAtk
Bold Nature (+Def, -Atk) / Modest Nature (+SAtk, -Atk)
When Garchomp was legal in 4th gen, Specsporeon was a popular choice as it dealt with it quite well. Surf is the standard reliable Water attack, but Hydro Pump is for people who LIVE ON THE EDGE. Way more power for a chance of missing... take the gain with the pain. Ice Beam pairs perfectly with your Water move and is so powerful that it took YacheChomp down in one hit, including the Yache damage reduction. Hidden Power [Electric] ruins Water Pokémon, but Hidden Power [Fire] is purely for Ferrothorn. Obviously, if you are using Vaporeon in Drizzle, don't run Hidden Power [Fire]. Baton Pass scouts for Ferrothorn and what not, but Shadow Ball hits Jellicent hard, and if you're running Hidden Power [Fire], you won't have any other move to hit the Water Ghost.
Baton Pass
- Substitute
- Baton Pass
- Wish
- Scald
Item Attached: Leftovers
Ability: Water Absorb
EVs and Nature:
EVs: 252 HP / 252 Def / 4 Spd
Bold Nature (+Def, -Atk)
Baton Pass teams are pretty much dead since Mean Look+BP got ruined, but that doesn't mean Baton Pass itself is bad. Vaporeon has a few moves it can pass, butSubstitute is easily the best thanks to its amazing HP. Baton Pass obviously sends you out and gives the Substitute (and any other boosts you have) to the Pokémon of your choosing. Wish can keep you alive, and heal the recipient. Scald stops you from being Taunt bait.
EVs & Natures
Vaporeon in general
Vaporeon is primarily a bulky Water, so treat it as such. Max HP (or near max) and max Defence gets you the most physically bulky you can possibly be. For the specs set, you can go either max Defence or max HP. Vaporeon already has over 400 HP, so it might be worth just going Defence and Special Attack. Baton Pass really depends on whether you are using it in a Baton Pass chain. If it is used in a chain, you might want to use Speed EVs.
Other Options
Acid Armor, Aqua Ring, Charm, Fake Tears, Yawn
Acid Armor is an alternative move to Baton Pass
Aqua Ring can also be Baton Passed, and acts as Leftovers.
Charm cripples a physical attacker and forces them to switch.
Fake Tears works really well on Vaporeon, as it gets 101 subs and has awesome Special Attack.
Yawn forces a switch or puts the opponent to sleep.
Double & Triple Battle Options
Water Absorb is handy in doubles and triples, as is Hydration on a rain team. Vaporeon also has a strong STAB Surf to abuse, but honestly, not much else. Nothing stands out in terms of double and triple options, and is generally outclassed by other Waters. Vaporeon should stick to singles.
Partners
Magnezone can remove Ferrothorn, which is every Water Pokémon's worst enemy. Heatran also does that job. Grass types work well in general as they resist Electric, as do Grounds like Excadrill and Gliscor. It's a standard bulky Water, so standard bulky Water partners work. In terms of Baton Pass recipients, you want Pokémon that can use the at least 1 turn set up to dominate a team. Lucario, Terrakion, that sort of deal.
Countering Vaporeon
Ferrothorn is the number one counter, but be careful of the rare Hidden Power [Fire]. Same with Celebi and other Grass Pokémon. Obviously, Blissey and Chansey wall you to high heaven. Tyranitar can take anything except Specs Surf and really hurt you with Crunch. Strong neutral physical attacks like Close Combat, Stone Edge, Return, they all deal good damage to you. Dragons can take anything but Ice Beam, but Dragons like Latias and Latios can take any move really. Espeon can Magic Bounce its way out of Roar and Toxic. Stuff that can Calm Mind up on you use you as set up bait, if you lack Roar. Obviously, offensive powerhouses like Breloom and Thundurus ruin Vaporeon, but can't switch in too well. Vaporeon is still a good Pokémon and definitely worth considering, be it on a drizzle team or on a team needing a bulky Water. It heals, it walls, it phazes, it's an all rounder and one of the best bulky Waters available.

Locations in Games
Ruby/Sapphire/Emerald:
Trade from FireRed/LeafGreen/XD
FireRed/LeafGreen:
Evolve Eevee.
Colosseum/XD:
Evolve Eevee (XD)
Trade from FireRed/LeafGreen (Colosseum)
Diamond/Pearl/Platinum:
Evolve Eevee.
HeartGold/SoulSilver:
Evolve Eevee .
Black/White:
Evolve Eevee
Transfer from Diamond/Pearl/Platinum/HeartGold/SoulSilver