The Ice Climbers can be unlocked in Super Smash Bros. Ultimate as a playable character in numerous game modes. They are one of the easier characters to unlock in the game, regardless of if you are using the Versus Method, playing through World of Light, or playing Classic.
If you are targeting the Ice Climbers specifically, your best bet is to play Classic Mode to unlock them as you only need to play through Classic Mode twice on easy difficulty to do so. Getting the Ice Climbers can be done in just a few minutes in Classic Mode. Simply head to this mode and select Link and beat Classic Mode with him on any difficulty. This will unlock King K. Rool. After you’ve done this you can just go back into Classic Mode and re-play it withe either Link or King K. Rool and you will get a challenge from the Ice Climbers after you’ve beaten it.
Unlock Ice Climbers in Classic Mode Quickly
The order you need to complete is as follows:
Link > King K. Rool > Ice Climbers
If you beat the Ice Climbers in the one versus one match, you will permanently unlock them to use in the game. If you lose to the Ice Climbers you will need to head back into the Challenger’s Approach in the Games and More section to rematch them and win to unlock.