Giant Skeleton, like any other Tank is best countered with swarm .
By far the best swarm in the game is the skeleton army.
But I've been countered with, and have been countering with a Witch or Barbarians , the later being quite popular among my enemies.
Pretty much anything that will keep him busy long enough to die, before reaching your towers.
The best strategy I'm aware of is to wait for it to come on your side of the map, and then place the army around him.
Even if the enemy has arrows or something similar, the skeleton would'be dead by the time they react.
Good point worth mentioning is, flying swarm is not good, as the skeleton ignores them and keeps going to the tower.
It will die eventually but not before dealing 1000+dmg to the tower ...
gaming.stackexchange.com/users/132203/Иво Недев
If you're at or above Pekka's Playhouse then including an Inferno Tower in your deck may help you counter this easily if you're seeing a lot of the Giant Skeleton.
Due to its nature this is actually true with any high HP targets, but it works really nicely against the Giant Skeleton because it means you don't have to sacrifice troops to his bomb.
Alternatively, if you can distract him with a low cost building like a Tombstone, attacking him with faster units like minions will allow them to leave the area before the bomb goes off.
The Giant Skeleton will run off the path to attack a Tombstone or other unit that is coming at him, so kite him away from your Crown Towers and isolate that bomb!
gaming.stackexchange.com/users/120054/Michael McQuade
My main deck uses Giant Skeleton , so I've seen a lot of defensive strategies.
To summarize: Hordes - Generally Giant Skeleton attacks slow, so he'll only take out one Horde troop at a time, and will get pummeled by the rest.
Minion Horde or Skeleton Horde will take him down in seconds.
Turning - Anything that kills the Giant Skeleton will promptly path right past his bomb.
To avoid this, put troops behind him once in your territory, so that they get clear before the bomb goes off. Kiting -
The best Elixir trade on a Giant Skeleton is to use cheap Horde troops like Skeletons or Goblins to kite him to the center and even across to the other lane.
This is most easily attempted when he is not backed up by ranged Area Damage troops like Wizards/Baby Drags (who will instantly splat cheap troops).
Inferno/
Other Towers - Giant Skeleton will target anything, so Towers/Huts are a great distraction, essentially similar to kiting.
The Inferno Tower is a positive Elixir trade if he is alone, but does need to build up enough DPS to take him down.
If the opponent is using Freeze, Zap, or has Hog/Horde backup watch out for it to be taken down to quickly.
Above all, the biggest priority is to keep the bomb away from your towers and avoid sacrificing too many troops to it.
gaming.stackexchange.com/users/21619/EBongo
Honestly, the Giant Skeleton is one of my favorite cards, I think however the giant skeleton can be easily countered as long as you remember these things:
Watch how much elixir you spend.
You want to spend 6 or less elixir to counter him since he costs 6 elixir to use.
Using goblins, valkyrie or even regular skeletons can distract the giant skeleton for a long time, hopefully long enough for you to kill it effectively.
Place troops behind it so after killing the skeleton they can run away
and hopefully you can form a counter-push. Inferno Tower Remember the range of the giant skeleton.
Round-abouts, place a fast, building targetting unit that isn't too fast behind the giant skeleton.
The giant skeleton will actually turn around and usually walk all the way back to the enemy's side to kill whatever (hog rider works well) and this allows you to cycle back to a small troop or save or a inferno tower or something.
Just know the giant skeleton, know it's stats, bomb damage, etc.
What other people have said, kiting, luring, etc.
Wait
until the bomb explodes before placing any troops, otherwise the troop will take unnecessary damage.
Remember, giant skeletons will keep walking if you use only air troops to counter it.
Good luck!
Sources: EXP and pushing to Royal Arena
gaming.stackexchange.com/users/146002/user146002
I typically drop a Pekka and a Prince.
They both have large amounts of damage and decent health.
I typically wipe out the Giant Skeleton before it touches my base with those troops.
gaming.stackexchange.com/users/133561/orias
A good strategy as mentioned by @h0ch5tr4355 is to drop the troops behind the Giant Skeleton.
Dropping something like barbarians behind it will cause it to turn around to attack them and after the barbs kill it, they can usually get out of the bomb explosion radius as they do not have to walk across the full area that is within the range of the bomb.
gaming.stackexchange.com/users/127901/Dragonrage
It is a good card against a Golem deck.
Otherwise, i think it's a bad card.
Can be pro actively countered with skeleton hut or any hut quite well.
Hordes or skelly army can be countered by the Giant Skeleton user with poison, arrows, wizard, queen, etc, which they'd most have and wouldn't count on as a good defense against the GS. Forementioned points of kiting and placing troops behind it are definitely valid.
He works well against golem because of the elixir swap and that you can't easily compliment that matchup as a golem user.
I've seen it work, but it's due to an elixir advantage that was manifested in an efficient defense gained earlier.
6 elixir for emergency defense is not good.
gaming.stackexchange.com/users/165936/transcend
If you have an inferno dragon, use it, but rage it.
If you don't have one, minion hordes do great damage, under rage.
You need to rage your troops because the giant Skelly can do insane damage to a tower, with it's hit, and it's bomb.
You don't want the giant Skelly to go near you.
When it's paired with valk, send in a mini pekka, and then do all of the above.
gaming.stackexchange.com/users/197170/Noob444
I keep facing people with Giant Skeletons and I haven't found a way to effectively deal with them. A lot of the troops have rather low hit points, so I tend to have to use several troops to kill it, but any that are alive after killing it tend to die when the bomb goes off.   So, what are effective cards to deal with a Giant Skeleton?
What troops can counter a Giant Skeleton?
gaming.stackexchange.com
<clash-royale>
gaming.stackexchange.com/questions/259401
gaming.stackexchange.com/users/127901/Dragonrage
Giant Skeleton is best countered with swarm.  If you're at or above Pekka's Playhouse then including an Inferno Tower in your deck may help you counter this easily. Minion Horde or Skeleton Horde will take him down in seconds.   The most common tactic to beat a Giant Skeleton, is to use swarms.
The community suggests few strategies.