Best counter-picks
These heroes are listed as strong answers into Bastion.
Tank
DoomfistBastion is easy to hit with Doomfist's Rocket Punch and Hand Cannon
SigmaSigma can almost completely negate Bastion's Configuration: Assault with Kinetic Grasp. Bastion is also easy to hit with Sigma's primary fire and Rock
Damage
HanzoBastion's large hitbox makes him very easy to hit with Hanzo's primary fire
ReaperBastion's wide hitbox makes him vulnerable to Reaper's spread
TracerBastion's wide hitbox makes him vulnerable to Tracer's spread
Support
WuyangBastion's large hitbox makes him very easy to hit with Wuyang's primary fire
AnaBastion's large hitbox and very slow movement in Configuration: Assault form make him vulnerable to Ana's Sleep and Biotic Grenade
BaptisteBaptiste can protect teammates from Bastion's ultimate and Configuration: Assault with Immortality Field
Favorable targets
Bastion is listed as performing well into these heroes.
Tank
WinstonBastion's Configuration: Assault has very high DPS, making it easy to break Winston's barrier. In Configuration: Assault form, Bastion is fairly tanky, so Winston's primary fire alone struggles to secure the kill
ZaryaBastion can melt Zarya right through her barrier
ReinhardtBastion can easily break Reinhardt's Shield
Damage
PharahPharah struggles greatly against Bastion in Configuration: Assault form
ShionSupport
BrigitteConfiguration: Assault 's firepower makes it difficult for Brigitte to close in
Jetpack CatBastion's primary fire is hitscan, making it easy to hit airborne targets
MercyBastion has strong anti-air capability. Mercy's healing often can't keep up with Bastion's damage output