There are currently 4 secret rooms in Club Penguin.
1.Captain's quarters (only when the migrator is in club penguin)
How - Get the key pin from the last page of captain rockhopper's diary (in the bookroom)
2.Ninja Hideout
How - Become a ninja.
3.Box dimension
How - Go through online igloos until u find one with a portal box (purple and swirly). When you find one walk over it.
4.Ocean room (i don't know the actual name)
How - get the key from the first level of the black puffle, puffle rescue. I am not a member so you should search for this video.
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the secret room douse not exist but the secret places are the mine and the dojo!
I realize it says in Club Penguin. Unlike the other idiot who answered but no. No houses in Club Penguin have any secret rooms......
He is in the testing room of the secret agen hide away .
because you stink
You rank up to the black belt and then you verse Sensei. If you win against Sensei you become a ninja! And then you Go to the dojo courtyard and waddle your penguin to the left and click on the door and your penguin will waddle to the secret room! Tada!