Swain is super squishy and immobile. Good times to trade with him are when he’s walked forward trying to harass.
When laning, make sure you’re always stood far back but in front of your Caster Minions. This will make it impossible for him to land his Root E and CC you.
At level 6, his kill pressure and survivability increases. Unless you have the advantage, disengage as soon as he activates his Ultimate R.
Swain is good in team fights thanks to his AOE Ultimate R. Forcing a fight or fighting when Swain isn’t around will make it easier for your team to win team fights.
Avoid grouping to closely around objectives or in team fights as it may allow Swain to land a really good multi-person E and start the team fight.
Burst and poke is the best way of winning a fight against Swain. Try to poke him down before a team fight starts. When he activates his Ultimate R, burst him down so he is unable to dish out lots of damage.
At level 6, Swain’s damage output and survivability increases. You shouldn’t commit to a fight with him unless you can burst him down quickly as his Ultimate R will offer him extra protection and health regeneration.
Swain’s early game is abusable as he is really weak early on. Once the mid-game hits, you’ll have to play more resectable.
He is really good in team fights thanks to his AOE Ultimate R. Bursting him down at the start of the fight will make it difficult for him to deal damage and win the fight.