#1007 · Gen 9 · Legendary

Koraidon — Best counters

Weaknesses

fairy×2.56 double weaknessflying×1.60psychic×1.60ice×1.60dragon×1.60

	Pokémon	Fast move	Charged move	Weather	Score
1	Gardevoir (Mega)	fairyCharm	fairyDazzling Gleam	Overcast	10018.2
2	Enamorus (Incarnate)	fairyFairy Wind	fairyDazzling Gleam	Overcast	8615.7
3	Alakazam (Mega)	psychicPsycho Cut	fairyDazzling GleamELITE	Overcast · partial	8515.5
4	Eternatus	dragonDragon Tail	dragonDynamax CannonELITE	Windy	8014.6
5	Zacian (Crowned)	steelMetal Claw	fairyPlay Rough	Overcast · partial	7914.5
6	Enamorus (Therian)	fairyFairy Wind	fairyDazzling Gleam	Overcast	7613.9
7	Xerneas	fairyGeomancyELITE	fairyMoonblast	Overcast	7613.9
8	Rayquaza (Mega)	dragonDragon Tail	dragonBreaking SwipeELITE	Windy	7613.9
9	Tapu Lele	psychicConfusion	fairyNatures MadnessELITE	Overcast · partial	7513.7
10	Gallade (Mega)	fairyCharm	psychicPsychic	Windy · partial	7513.6
11	Gardevoir	fairyCharm	fairyDazzling Gleam	Overcast	7313.2
12	Hatterene	fairyCharm	fairyDazzling Gleam	Overcast	7313.2
13	Eternatus (Eternamax)	dragonDragon Tail	dragonDynamax CannonELITE	Windy	7213.2
14	Tapu Koko	normalQuick Attack	fairyNatures MadnessELITE	Overcast · partial	7213.2
15	Togekiss	fairyCharm	fairyDazzling Gleam	Overcast	6912.6
16	Garchomp (Mega)	dragonDragon Tail	dragonBreaking Swipe	Windy	6912.5
17	Salamence (Mega)	dragonDragon Tail	flyingFly	Windy	6812.4
18	Primarina	fairyCharm	fairyMoonblast	Overcast	6812.4
19	Tapu Bulu	grassBullet Seed	fairyNatures MadnessELITE	Overcast · partial	6812.3
20	Xurkitree	electricThunder Shock	fairyDazzling Gleam	Overcast · partial	6812.3

Fairy hits for ×2.56 — Koraidon's Fighting/Dragon typing is double-weak, so those attackers outperform their score gap.
Watch its Fighting/Dragon/Normal moves — counters like Eternatus and Rayquaza (Mega) take super-effective damage from them.
Overcast weather boosts Fairy moves ×1.2 — the best time to battle Koraidon.

Rankings are estimated cycle DPS (attack stat × move damage ÷ cycle time, with STAB and type effectiveness). Not a full battle simulation.