Heatran is a force to be reckoned with in the OU tier. With one of the highest Special Attacks in the tier it makes quick work of anything not resisting its STAB Fire Blast and even several who do. As if base 130 Special Attack wasn't strong enough, Flash Fire boosts Fire attacks by 1.5x when Heatran takes a Fire attack (which is nullified). Heatran's plethora of resistances, including x4 resistance to Ice, Steel, and Bug and an invaluable Dragon resist, combined with impressive defenses and HP provide Heatran with many switch ins beyond Fire attacks. Heatran doesn't stop there: a versatile movepool and well distributed stats allow Heatran to fulfill many jobs depending on what your team needs. Access to Fire Blast, Flamethrower, Lava Plume, Magma Storm, and Overheat gives Heatran several options for Flash Fire boosts. Earth Power, Dragon Pulse, various Hidden Powers, and Explosion make up the majority of Heatran's other offensive options, several of which can help Heatran overpower its counters. Stealth Rock and Taunt added into the mix not only make Heatran an excellent supporter for the team, a potent lead, and Taunt can help Heatran break walls like Blissey if it lacks any way to damage Heatran. Though the Choice Scarf set is the most common, Life Orb and tanking Heatran sets are quite common along with the Shuca Berry lead. Heatran's downfall is it's weakness to the very common offensive types Ground (x4), Fighting, and Water. Heatran's disappointing base 77 Speed though useful prevents Heatran from outrunning vital threats without Choice Scarf.
Generally bulky Water-types such as Vaporeon, Milotic, Tentacruel, and Suicune
all make good counters to Heatran as they resist Heatran's heavy Fire attacks and hit back hard with STAB SE Surf. Gyarados
can deal with Heatran though Stealth Rock, Sand Storm, and frequent burns is a major hamper on Gyarados' effectiveness. Gardevoir and Porygon2
can switch into Heatran's Fire attacks and Trace Flash Fire. Gardevoir is the better of the two having a much higher Special Defense though Porygon2 has better overall bulk and access to Recover rather than Wish/Protect is valuable. Latias and the best Fire resist in the tier, Kingdra,
can switch into everything but Dragon Pulse (Hidden Power Ice can be dangerous against Latias) and set up. Certain Blissey sets
make good counters as they can sponge up even Flash Fire boosted Fire Blasts but need something to hit back with to be a true counter as Taunt sets will quickly tear Blissey down. Protect/Wish Blissey is especially effective as it can scout and render Explosion useless which would otherwise drop her. Heatran
acts as a counter to itself as long as it watches out for Earth Power as it resists everything it can normally hit with and absorbs Fire attacks. Choice Band Dugtrio and Choice Scarf Magnezone
can both trap Heatran and OHKO with respective Ground attacks but must be extremely cautious since neither can outrun Choice Scarf sets and are easily KO'd by any Fire attack and in Magnezone's case, Earth Power as well. Dugtrio's lack of bulk prevents it from switch into anything but Hidden Power Electric. Snorlax and Hariyama with Thick Fat
resist Heatran's STAB attack and hit back hard with SE Fighting or Ground attacks. Tyranitar
resists Fire-type and with it's ability gets a healthy Special Defense boost and with investment a defensive Tyranitar isn't even 4HKO'd by SE Earth Power while easily OHKOing with Earthquake.
~Counter Measures (Lead)~Swampert
, especially those with Protect for Explosion, can deal with Shuca Heatran leads since Fire Blast and Earth Power never deal enough damage without a positive nature and/or a boosting item. Infernape
can make quick work of Heatran with Close Combat. Gliscor and Aerodactyl
outrun and aren't OHKO'd by Fire Blast while hitting back hard with Earthquake. Both also have Taunt to prevent Stealth Rock. Machamp and Dragonite
are all outrun but always OHKO with respective Fighting attacks (Dragonite will OHKO with Earthquake as well) and are not OHKO'd by Fire Blast. Faster Sleep leads Roserade and Crobat
can attempt to put Heatran to sleep since lead Heatran never runs Lum Berry. Mamoswine
outruns and scores a OHKO with Earthquake 80% of the time. Tyranitar
walls Heatran quite easily and makes quick work of it with Earthquake or Superpower.