The Skylands is a place which is almost impossible to get to in Minecraft. The steps to get there have only been tested in MCPE. It is also recommended that you do not go there, as weird stuff may happen and crazy stuff may happen. It could also crash Minecraft or corrupt your world.
PROCEED WITH CAUTION
First, start a new world with cheats enabled. It can be in Survival, or Creative. Then run the following command:
/tp ~ ~1000000 ~
The game will lag a bit but then you will be teleported to the Skylands. To die, the only known way is to use harmful potions on yourself or to use /kill @p. That is why it is not recommended to go there.
You could also bump into some absolutely crazy mobs.
I am not responsible for lag or game crashes whilst exploring.