When defending against a Bowler that is on the player's side of the Arena, avoid placing the defensive card in front of him, as there is the risk of incurring damage to the tower. Instead, place the unit(s) in the center, so the boulder is directed away from the tower.
It is important to place the Bowler correctly, as to make the most use out of his linear rolling attack. For example, if there is a big push with many low hitpoint troops hiding behind a tank, then the Bowler should be placed directly in front of the tank so his boulder will roll over all the troops behind it.
The Bowler is a very effective counter to cards that spawn other units such as the Barbarian Hut and Goblin Hut, as he constantly pushes the spawned units back and deals damage to all of them.
He is an excellent counter to a push, damaging both the tank and the backup. More importantly, his boulder separates the backup from the tank (Giants, Golems, and P.E.K.K.A.s aren't affected by pushback), making them easier to finish off.
The Bowler is excellent defending against small to medium health troops since they can be crippled by the Bowler's considerable damage and knockback, if not destroyed outright.
When defending against a Bowler, Minions, a Minion Horde, or an Inferno Dragon can easily take him out since the Bowler only hits ground troops. It is also possible to surround and defeat the Bowler with cheap ground units due to his slow, linear attack. Barbarians and Guards work very well when surrounding him, due to their damage.
Since surrounding the Bowler can destroy him easily, the player should use strong splash units to take out the units surrounding the Bowler.
If placed directly behind an Arena Tower, the Bowler can counter a Goblin Barrel and stay alive for a counter-push. However, this requires good timing.
He has a slow hit speed and low damage per second, so the player might need to back it up with troops with fast attack speeds and hard hitters such as the Musketeer and the Witch.
He can take out the Witch with ease because he can also damage the Witch while killing the Skeletons. When used properly, he will suffer minimal damage and still make a good counter-push.
On 24/8/16, a Balance Update decreased the Bowler's Elixir cost to 5 (from 6), decreased its hitpoints by 7%, and its damage by 10%.
On 19/9/16, the September 2016 Update changed his description. The description used to say "This big blue dude digs the simple things in life - Dark Elixir drinks and throwing rocks. His massive boulders bounce off their target, landing behind for a double strike."
He is the first troop that can push back other troops with its attack, and also the first one with a linear rolling attack that can go right through units.
The description was taken from Clash of Clans, though there actually isn't Dark Elixir in the game. Also, before the September Update, the description used to be wrong, as the boulder rolls, not bounces.
Although the Clash Royale Bowler is similar to his Clash of Clans counterpart, in Clash Royale his rocks actually roll while in Clash of Clans they bounce.