Eevee is a gift Pokémon, obtainable by talking to Bill in the Ecruteak City Pokémon Center and then visiting his house in Goldenrod City. Other Eevee may be purchased from the Celadon City Game Corner.
Psychic-types are generally quite good in game, and Espeon is no exception. Unfortunately, it faces competition from Alakazam, Hypno, Girafarig, and even the Togepi from Professor Elm for a spot on the team as the Psychic user, leaving Espeon, at first glance, not quite worth the trouble of friendship grinding. However, Espeon's unique combination of Speed, power, and supporting movepool help to set it apart from its brethren, allowing it to survive hits that Alakazam could not, without sacrificing sweeping potential.
Rival (Burned Tower): Gastly and Zubat can be be one-shotted with Confusion if you have Espeon by now. However, Magnemite resists Psychic moves and the Starters are all risky. Croconaw is the worst since it has Bite to hit super-effectively on Espeon's weaker defense. More doable are Quilava, who can hit relatively hard with Flame Wheel and will annoy you with Smokescreen but is 3HKOd by Confusion, and Bayleef, who is bulky and carries Poison Powder and Synthesis. However, Synchronize will pass the Poison status back to Bayleef, which can be handy if you're having trouble wearing it down.
Gym #4 - Morty (Ecruteak City, Ghost-type): If your Espeon is at level 25 and does not have a Speed or Defense-lowering nature, it can handle all of Morty's Pokemon except his ace. Espeon takes advantage of its high base speed and OHKOs his Gastly and both Haunter with Confusion. The level 23 Haunter has Sucker Punch, but this should not even OHKO with a crit. Avoid the Gengar completely.
Eusine (Cianwood City): Both Drowzee and Haunter carry Hypnosis, which will drag this battle out much more than you want. Haunter also has Mean Look, which could accidentally trap your Espeon in with his Electrode. It's a lot more effort (and risk) than it's worth, so just attempt Drowzee if you want and avoid the other two.
Gym #5 - Chuck (Cianwood City, Fighting-type): Psybeam, more like Why-beam is it not here yet. Confusion just barely misses out on OHKOing Primeape. None of its moves are dangerous enough to OHKO Espeon, but it tends to set up Double Teams and can mess you up with Focus Punch if you can't hit it. So it's up to you if you want to risk it. An Espeon with a Special Attack boosting nature can guarantee the OHKO with a TwistedSpoon. Poliwrath is similarly dangerous with Hypnosis and cannot be OHKOd with Confusion. It's best to avoid this matchup, but it is possible if you take a few risks.
Gym #6 - Jasmine (Olivine City, Steel-type): Not a good idea, as everything resists your STAB and coverage unless you get lucky with Hidden Power. If you over-level slightly to get Psybeam, both Magnemite can be 2HKOd. Watch out for Supersonic. Steelix has pretty bad Special Defense, but you're better off using something whose attacks are not resisted, particularly considering how hard Iron Tail can hit Espeon.
Petrel (Team Rocket HQ): If you're here after Chuck and Jasmine, you'll be ridiculously overleveled and this will be a breeze. All three will go down to Psybeam. At fair levels, Zubat and Koffing should still go down easily with confusion, but beware of Raticate, who knows both Crunch and Sucker Punch.
Ariana (Team Rocket HQ, tag battle with Lance): Tag battles are always risky because there's an element you can't control. Murkrow is immune to Psychic moves and Arbok knows Crunch, so be careful around this fight. Espeon should be able to deal with Drowzee (if you have Shadow Ball), Gloom and Grimer, but it is difficult to engineer a situation where this is possible. Of course, if you're overleveled, you can just nuke everything except Murkrow with Psybeam again.
Gym #7 - Pryce (Mahogany Town, Ice-type): This fight can be very annoying, but Espeon can be useful here. Shadow Ball is probably the best move to use, as it not only hits harder than Confusion after STAB, but has a chance to lower Special Defense, making it easier to wear down his Dewgong. Make sure you stall out Hail before the Piloswine comes in, Snow Cloak is both annoying and dangerous.
Petrel (Goldenrod Radio Tower): Did somebody say murder? Spam Psybeam. This fight is a joke if you have anything with strong Special attacks; SE STAB from base 130 Special Attack is just overkill.
Rival (Goldenrod Underground): He has a Sneasel now, which Espeon should not fight. Golbat and Haunter are easily taken care of with Psybeam. Magnemite is possible but can be annoying with Supersonic. Quilava is safe to fight, Meganium now has Petal Dance, which can wear down Espeon along with PoisonPowder. Definitely avoid Feraligatr, who now packs Crunch.
Proton (Goldenrod Radio Tower): Second verse, same as the first. Psychic STAB destroys everything.
Ariana (Goldenrod Radio Tower): The only problem member of her team is the Murkrow; just Psybeam the heck outta Arbok and Vileplume.
Archer (Goldenrod Radio Tower): Espeon can deal with the Koffing, but should stay well away from Houndour and Houndoom.
Gym #8 - Clair (Blackthorn City, Dragon-type): Espeon can actually help out a bit here, since Swift ignores Kingdra's Smokescreen and Synchronize can give some time to heal the paralysis from Thunder Wave before Shed Skin kicks in for the Dragonair pair. Both Dragonair will be 2HKOd by Psybeam. Kingdra is possible if you set up X Sp Atks on Dragonair. You need to be able to OHKO it because a critical hit will OHKO Espeon with Sniper.
Kimono Girls (Ecruteak Dance Theater): All of the Eeveelutions have decent Special Defense or better, but Espeon can put in work here against some. If you have Shadow Ball, the opposing Espeon goes down fairly easily. Vaporeon, Flareon and Jolteon are toss-ups. You don't have SE coverage for them and they can all hit back hard. Umbreon should be handled by someone else.
Ho-Oh (Bell Tower, HeartGold only): Sacred Fire alone is reason enough not to attempt this, but this is also a good time to point out that Espeon's best STAB is still base 65.
Lugia (Whirl Islands, SoulSilver only): This is possible at level 45, no lower. While Rain boosted Hydro Pumps and STAB Aeroblasts will not be fun to tank, Lugia actually has pretty low Special Attack for a legendary (Base 90), and after the 5 pp each is used up, it will have to resort to resisted Extrasensory, while Espeon can whale away with Shadow Ball. If you plan to catch this behemoth, either suck it up and chuck the master ball, or have Kurt make a crap load of Heavy Balls, which has a whopping 11x the chance of catching Lugia compared to a regular Pokéball.
Rival (Victory Road): Once more with feeling! Golbat and Haunter are easily taken care of with Psybeam. Magneton is suddenly more threatening, avoid it along with Sneasel. Typhlosion is safe to fight, Meganium's Petal Dance can wear down Espeon along with PoisonPowder. Definitely avoid Feraligatr, who packs Crunch. Kadabra is relatively easy to handle if your Espeon has Shadow Ball.
Elite Four Will (Indigo Plateau, Psychic-type): If you have Choice Specs and Shadow Ball, his team should go down fairly easily. Without either, though, it'll be an uphill battle. You'll have to use Swift, preferably with a Silk Scarf/Choice Specs on you. His lead Xatu has U-turn and his ace has Ominous Wind, so be careful against them. Additionally, if Slowbro starts to set-up Amnesia, Espeon will not be able to beat it.
Elite Four Koga (Indigo Plateau, Poison-type): Espeon should be able to sweep most of Koga's team rather easily, and that goes double if you have Choice Specs. Forretress is the exception as it resists Psychic moves. And also, it can use Explosion. So leave that one to someone else unless you rolled a high BP Hidden Power Fire.
Elite Four Bruno (Indigo Plateau, Fighting-type): Again, Espeon should be able to sweep with Psybeam and Choice Specs, even against Onix because of its poor Special Defense.
Elite Four Karen (Indigo Plateau, Dark-type): You can deal with the Vileplume and the Gengar easily. But do yourself a favor and stay far away from everyone else since Espeon has nothing it can hurt them hard enough with and you will regret it if you let Houndoom set-up Nasty Plot.
Champion Lance (Indigo Plateau, Flying-type): Everything here has pretty good Attack and Espeon's low Defense won't allow it to tank their strong physical attacks, particularly his ace's Outrage. As such, this battle is risky and Espeon should stay out if you have safer options.
From this point onwards, you can fight the gyms in any order, though you will need to retrieve the Machine Parts from the Cerulean City gym before you have access to the earlier portion of Kanto. Feel free to anticipate or postpone any battles as needed.
Gym #9 - Brock (Pewter City, Rock-type): If you have Grass Knot, this battle should be a joke. And even without it, Espeon hits their weaker Special Defense very hard with STAB Psychic, even OHKOing most of them. If you don't have Grass Knot, avoid Kabutops, which can kill Espeon with a critical hit Rock slide and has Aqua Jet to bypass Espeon's high speed.
Rival (Mt. Moon, optional): Golbat and Gengar are obliterated by Psychic or Psybeam. Alakazam is also safe to handle with Shadow Ball or Signal Beam. Magneton is possible, but can be annoying with paralysis. Avoid Sneasel and all three starters.
Gym #10 - Misty (Cerulean City, Water-type): Grass Knot is clutch in this battle if you have it. It OHKOs Golduck and Quagsire if Espeon has Specs, and will 2HKO Lapras and Starmie. Without it, this battle is a little more challenging. Psychic can deal significant damage as well, but Misty's strategy relies on team support, so it's better if her Pokémon don't have a chance to set up.
Gym #11 - Lt. Surge (Vermilion City, Electric-type): One Electrode can use Selfdestruct and there is no way to tell them apart since they are at the same level. It is safer to avoid both. Otherwise, this should be easier than the Elite 4, especially if your Espeon has Choice Specs Psychic now. Even Magneton is 2HKOd by it.
Gym #12 - Erika (Celadon City, Grass-type): Most of her team is pretty weak and her strongest, Victreebel, is part Poison-type. Espeon OHKOs it with Psychic and can also OHKO Tangela. The most important part of this battle is not allowing her to set up Sunny Day with Jumpluff, so lead with something that can OHKO it. Bellossom becomes dangerous if it has access to fast, single-turn SolarBeam.
Gym #13 - Janine (Fuchsia City, Poison-type): Espeon should sweep this gym rather easily, unless you got really unlucky with Speed IVs and its nature.
Gym #14 - Sabrina (Saffron City, Psychic-type): Sabrina's team is a little more threatening than it looks on paper, and that's because of her own Espeon. Just watch out for its powerful Shadow Ball, the other two will go down to Specs Shadow Ball or Signal Beam without risk.
Gym #15 - Blaine (Seafoam Islands, Fire-type): Be careful in this fight as, while Espeon can hit them hard, it'll take lots of damage back. Magcargo can be OHKOd by Choice Specs Psychic, and Magmar is 2HKOd by it. However, you do not want to give Blaine a chance to set up Sunny Day and have a team member take a STAB Flare Blitz in the sun, so it’s probably better to use a ‘mon that’s capable of one-hitting them.
Gym #16 - Blue (Viridian City): Pidgeot and Machamp shouldn't be too hard. Leave Gyarados and Arcanine to other Pokémon, as they have good Special bulk. Exeggcutor will survive a Psychic and likely set up Trick Room, so don't fight it without Shadow Ball or, better yet, Signal Beam. Rhydon has Megahorn, so leave that thing alone unless you're absolutely certain you can switch in safely to OHKO with Grass Knot.
Rival (Indigo Plateau, optional): Again, avoid Sneasel. It does too much damage. Again, Gengar and Crobat are easily dealt with since your Espeon should pack Psychic. This time, Crobat may outspeed and use Bite, but it won’t OHKO with a crit, so it is safe unless Espeon flinches. Alakazam will be easy if you still have Shadow Ball or Signal Beam. Typhlosion and Meganium are easier than usual, 2HKOd by Psychic if you carry a TwistedSpoon. As usual, avoid Feraligatr though, Crunch is just too powerful.
Red (Mt. Silver): Stay away from this fight until at least level 85. One trick Espeon can use here is setting up Sunny Day or Rain Dance to turn off Red’s hail. This removes chip damage from your team and makes Red's numerous Blizzards less accurate. Pikachu is easily taken care of with Psychic. You have no room to set up weather on it though, since Light Ball boosted Volt Tackle will hurt a lot if not outright OHKO. The rest of his team is fairly bulky. If you allow battle items, set up a Special Attack boost or two on Lapras. Lapras and Blastoise are both be 2HKOd by Grass Knot, OHKOd if you set up. Protect may help in this battle if you can correctly predict when the starters will use their strongest moves. Snorlax's high Special Defense and Attack stats throw Crunch and Giga Impact at you. Avoid it completely. Venusaur should pose no problem for Espeon. Charizard's Flare Blitz will do tons of damage, so avoid it. Miracle Seed is a good held item for this fight.
Bill’s Eevee starts with “Tackle”, “Tail Whip” and “Helping Hand”. None of these are very useful in the long run. At level 8, “Sand-Attack” will allow you to lower the opponent’s accuracy. Not all that great, but it’s better than nothing. It is recommended that Eevee be evolved by level 15 so that Espeon won’t miss out on “Confusion” at that level, which will be its first STAB Psychic-type move. However, after level 15, Eevee gets “Bite” at level 29 and “Baton Pass” at level 36. Bite is helpful in the early game, but works off Espeon’s weaker offensive stat. Baton Pass is only really useful in the postgame.
At level 22, Espeon learns Quick Attack, which is generally unnecessary for a fast Pokémon like Espeon, but better than Tackle. Level 29 boasts Swift, Espeon's only naturally learned special coverage move and much stronger coverage than Tackle or Quick Attack. At level 36, Espeon gets Psybeam as an upgrade to Confusion. You'll be carrying it all the way to Kanto, where a better STAB move will come along. Future Sight comes at level 43 and, while powerful, is hard to use effectively and may not be better than just shooting Psybeams. Last Resort and Psych Up come at levels 50 and 57, respectively, and generally aren't worth using. At level 64, it finally learns Psychic to replace Psybeam. Level 71 gives you recovery in Morning Sun which is useful if your items and/or Pokémon Center use are restricted. Finally, Power Swap is learned at level 78, but it is not helpful at all.
Espeon also gets quite a few good moves by TM. Calm Mind is useful for both offensive and supporting roles, but the TM is Battle Frontier only. Hidden Power is an option for coverage, particularly if it is Fighting, Fire or Ground-type. Even with a low BP, Espeon’s base 130 Special Attack allows it some use in both Johto and Kanto. Psychic is available as a TM too. Shadow Ball is a must-have on attacking sets as it comes very early, has great base power, and gives good coverage against opposing Psychic-types. Signal Beam as a Battle Frontier tutor move can fill the same role, trading some power and early availability for hitting Dark-types super effectively. Grass Knot and Hyper Beam are the last two attacking moves worth mentioning. Grass Knot provides good power on the heavier Pokémon seen in late game and coverage for bulky Water-types. Hyper Beam can be devastating off Espeon’s high Special Attack, though the recharge isn't normally worth it after the Johto Elite 4. In terms of support, Espeon learns Substitute, Sunny Day, Rain Dance, Light Screen, and Reflect by TM. Also, Heal Bell is an option by move tutor and usable thanks to Espeon’s Synchronize.
Minimum stats are calculated with 0 EVs, IVs of 0, and a hindering nature, if applicable.
Maximum stats are calculated with 252 EVs, IVs of 31, and a helpful nature, if applicable.
What Nature do I want? Modest is probably the best, followed by either Calm or Bold, with Timid behind those. Anything that reduces Special Attack means you should probably look into a different Eeveelution, especially if you get Adamant. Speed-lowering natures also aren’t recommended.
At what point in the game should I be evolved? Generally, you'll want to evolve before level 15 so you can get Confusion, which means a long time of friendship grinding. If you want Baton Pass for a support set, wait until level 36, but keep in mind you'll have to go to the Battle Frontier to benefit from this move.
How good is Espeon in a Nuzlocke? While it does face stiff competition from the likes of Alakazam offensively and Hypno defensively, Espeon is still a fine Pokémon. As limited as its movepool is, it can fill an attacking or supporting role for your team, depending on what you need. This alone helps it find a place on the team no matter what else you have.
Eevee's type matchups:
Neutralities: Normal, Flying, Poison, Ground, Rock, Bug, Steel, Fire, Water, Grass, Electric, Psychic, Ice, Dragon, Dark