Celesteela is a durable mixed wall that is capable of taking on several dangerous Pokemon, such as Mega Diancie, Landorus-T, and Tapu Lele. Heavy Slam is the preferred STAB move thanks to Celesteela's high weight, giving it a high Base Power much of the time. Flamethrower lets Celesteela pressure Steel- and Grass-types such as Ferrothorn, Gholdengo, Kingambit, and Corviknight. Leech Seed allows Celesteela to spread chip damage onto switch-ins like Heatran, Raging Bolt, and Zapdos while simultaneously keeping itself healthy; it also dissuades offensive Pokemon like Great Tusk, Zamazenta, and Terapagos from attempting to slug it out with Celesteela one-on-one. Protect allows Celesteela to rack up Leftovers and Leech Seed recovery while also scouting moves from opponents like Tapu Lele and Iron Valiant. Leftovers is crucial to give Celesteela as much recovery as possible. 16 Defense EVs and a Relaxed Nature allow Celesteela to take two Mega Lopunny Close Combats from full health. The rest of the EVs are invested into Special Defense to check threats like Tapu Lele, Mega Diancie, and Mega Latios as well as possible.

Celesteela fits best on balance and bulky offense teams that appreciate its walling capabilities but can compensate for its noticeable passivity against certain matchups. Bulky Poison-types have notable defensive utility with Celesteela: Pecharunt, Galarian Slowking, and Toxapex appreciate Celesteela taking on Tapu Lele, Mega Latios, and Gliscor for them. These teammates can take on Fighting-types such as Zamazenta and Mega Lopunny, which Celesteela does not appreciate taking multiple hits from. Dragon-types also have notable defensive synergy with Celesteela, as they can take on Fire-, Electric-, and Water-type attacks for it while Celesteela takes on dangerous Fairy-types. They especially appreciate Celesteela's status as one of the best Mega Diancie and Tapu Lele answers available. Dragonite, Raging Bolt, and Mega Latios make for good partners as a result, as they can check threats such as Mega Charizard Y, Heatran, and Ogerpon-W for Celesteela. A main flaw of Celesteela is its inability to dissuade certain very dangerous setup threats, most notably Gholdengo, Volcarona, and Raging Bolt, from freely boosting in its face. It is necessary to have solid checks to these boosted threats as a result. Ground-types like Ting-Lu and specially defensive Garchomp can help out against these threats even after they have had an opportunity to boost. Moltres is another good option to help out with these threats specifically, and it also gives Celesteela an additional Fire-resistant teammate. Celesteela also struggles to appreciably threaten Regenerator cores featuring Pokemon such as Toxapex, Galarian Slowking, and Slowbro, so a strong wallbreaker that can disrupt them, such as Ogerpon-W, Garchomp, or Raging Bolt is a good partner. A Knock Off absorber is very important, as Celesteela loses a significant amount of its longevity if it loses its Leftovers. A teammate such as Gliscor, Clefable, or Mega Venusaur is a valuable teammate as a result.

Celesteela makes the most of its typing, utility options, and great natural bulk on both sides to serve as a fantastic wall, capable of holding teams together against threats such as Aegislash, Excadrill, and Mega Latias. Leech Seed serves as Celesteela's main recovery move, capitalizing on the many switches it forces while also being able to deter incoming walls such as Rotom-Wash and Hippowdon, which may otherwise try and take advantage of it. Heavy Slam acts as Celesteela's main STAB attack; with its massive weight, Celesteela threatens to OHKO Iron Boulder, Mega Aerodactyl, and Alakazam, on top of being able to 2HKO physically defensive Clefable. On the other hand, Air Slash deals more damage to Grass- and Fighting-types such as Amoonguss, Mega Venusaur, and Keldeo, preventing the former two from switching in to absorb its Leech Seed and deterring the latter from trying to use it as setup fodder. Protect allows Celesteela to accrue recovery from Leech Seed and Leftovers as well as scout the intentions of Choice item users such as Tyranitar. However, Toxic is also a relevant option, assisting Celesteela against Regenerator pivots such as Assault Vest Tangrowth, Slowbro, and Slowking. Flamethrower OHKOes most Scizor sets and provides a coverage option for other Steel-types such as Aegislash, Skarmory, and opposing Celesteela. Alternatively, at the cost of its ability to hit several of the aforementioned Pokemon, Earthquake gives Celesteela a more reliable option to hit Iron Moth and Magnezone, preventing them from KOing it in return. Maximum HP and Special Defense investment give Celesteela the best odds at surviving attacks from the likes of Alakazam, Hydreigon, and Aegislash. Alternatively, 96 Defense EVs in conjunction with a Relaxed nature improve Celesteela's ability to take on physical attackers, most notably avoiding a 2HKO from Choice Band Iron Boulder's Mighty Cleave after Leftovers recovery. Defensive Celesteela fits best on bulky offense and balance teams that appreciate its lack of passivity over Skarmory, being comfortable with falling back on it without losing momentum against threats such as Mega Latias and Hydreigon. Walls such as Amoonguss, Hippowdon, and Slowking appreciate Celesteela's ability to help cover several of the aforementioned Dragon-, Psychic-, and Grass-type threats. In return, they can help supplement Celesteela's ability to spread chip damage through the use of entry hazards or status moves as well as answer threats that may overwhelm it, such as Swords Dance Iron Boulder and Keldeo. On the other hand, faster revenge killers such as Zeraora, Choice Scarf Mienshao, and Sand Rush Excadrill are similarly effective at keeping these Pokemon, as well as other setup sweepers such as Galarian Moltres, in check; the former two are also able to assist Celesteela in breaking down walls with Knock Off, whereas Excadrill can utilize Rapid Spin to ensure it isn't being worn down by Stealth Rock. Lastly, Celesteela is very reliant on Leftovers for recovery; the likes of Clefable, Rillaboom, and Alakazam can opt to exploit this by luring it with Knock Off; thus, Knock Off absorbers such as Mega Venusaur and Scizor can prove vital while attempting to scout these Pokemon.

Celesteela's high Special Attack, good movepool, and snowballing potential with Beast Boost make it a great sweeper when using Autotomize to shore up its poor Speed. Its naturally great bulk and Steel/Flying typing afford it setup opportunities against foes like Scizor and Excadrill, as well as the ability to easily muscle past them. Meteor Beam combined with Power Herb lets Celesteela boost its Special Attack without needing a KO. Given that it's Celesteela's strongest attack, in some situations it should be saved to instead target a foe Celesteela would otherwise have trouble breaking through like Skeledirge or Victini. Air Slash serves as a spammable STAB attack, 2HKOing most of the tier at +1, though it can OHKO many Bug- and Fighting-types like Buzzwole and Mienshao unboosted. Its chance to flinch its foes can also come in handy against special walls like Gastrodon and Slowking, which could otherwise stop Celesteela's sweep. Fire Blast primarily targets Steel-types, OHKOing foes like Scizor unboosted and opposing Celesteela after a few boosts. Celesteela best fits on offense teams looking for a cleaner, forming a potent offensive combination with other sweepers like Bisharp. Alternatively, if the opportunity arises, it can instead be used as a mid-game wallbreaker and have a teammate clean using the holes it creates. However, it has no way to break through certain special walls like Blissey and Chansey on its own, making physical attackers like Bisharp and Mienshao necessary. While they share some overlapping counterplay, special sweepers like Booster Energy Iron Moth and Galarian Moltres also appreciate Celesteela's support for similar reasons, and they can still support each other by weakening some of each other's shared checks, such as Slowbro, Slowking, and Mega Latias. Entry hazard setters like Lead Mew and Excadrill are crucial for their ability to weaken Celesteela's checks, making it harder for foes like Gastrodon and Assault Vest Iron Crown to remain healthy enough to check Celesteela.