Sojourn is extremely frustrating for Bastion mains, as I can also contest as someone who also plays Bastion quite frequently. Sojourn has a very aggressive and effective primary fire that can just obliterate him.
She is extremely tough to follow with your weapon sights, so if you want to try to defeat Bastion, using her slide and agile ability will give her the advantage against his ultimate ability and primary weapon. As I have played Sojourn many times, she is my go-to for when everything is going wrong, as long as Sojourns counters aren't being played, which can lead to defeat.
Widowmaker can easily shut down a Bastion, especially with headshots. Widowmaker can spot Bastion seamlessly behind enemy lines, and cancel his Ult effectively. I have experienced this firsthand... and I have to say being Bastion in this situation really made it difficult to claim victory!
There are not many Overwatch heroes to counter Widowmaker, and Bastion is one of the worst! You can easily defeat Bastion with the high ground and using your best defensive abilities with long distances.
Hanzo is another really great hero at countering Bastion. Similar to Widowmaker, his arrows can make effective headshots to bring Bastion to one health bar immediately. This is extremely effective, and very annoying for me when I play as Bastion.
Along with Hanzo's primary weapon, his Sonic Arrows can easily track Bastion's movements making him an easy target. If you continuously keep your arrows on Bastion, you will definitely find a victory against him as a Bastion counter.
Sigma is a great defense matrix against Bastion, making him a fantastic hero to counter Bastion in Overwatch 2. Sigma eats damage for breakfast as a tank hero, especially Bastion's main weapon and even his turret. I find myself having a lot of trouble countering Sigma as a Bastion player.
As Sigma stands as super bullet spongy, he can also destroy Bastion with his Ult, receiving no mercy and being smash into tiny robot pieces. Rest assured, you can really frustrate a lot of Bastion main's with a good Sigma in your team fight.
Orisa has fantastic defensive mechanisms to counter Bastion effectively, while also returning his damage back to himself. With Orisa's Javelin Spin, you can easily deflect Bastions aggressive minigun and counter the damage back to him.
Orisa's Energy Javelin also makes Bastion an easy target and be stopped in his track immediately. She is extremely annoying as a tank against Bastion, making her one of the most effective heroes as a Bastion counter.
Genji frustrates so many players no matter the hero, although, for Bastion counters, he is a special case. Genji's deflect works really effectively against Bastion, similar to Orisa's Javelin Spin, creating an impossible offensive position for Bastion to gain any ground.
With Genji's fast movements, flanking ability, and overall damage output, he is sure to bring down any good Bastion player.
Ashe stands as a fan favorite counter for Bastion as her ultimate ability can put down his turret almost immediately. Many Bastion main players are super annoyed with Ashe as well which makes her one of the best Bastion counters.
If you are ever needing to counter Bastion in Overwatch, using Ashe's primary fire will greatly reduce Bastions health to help easily counter his aggressive offense. This along with B.O.B will guarantee to deal damage significantly to put your team in a winning position.
Although Ana's focus is mainly being the best of the support characters, she does have a good advantage being a Bastion counter. With her sleep dart, Bastion can easily be defeated by surrounding enemies without a good healer nearby to help him up.
Usually, with Ana's sleep dart, Bastion immediately gets his minigun ability cancelled, which has a pretty long cooldown to be reused again. With this, Ana brings her team to a fair fight, and gives them the high ground against the enemy.