In reply to HakanT:
Hi,
There really are lots of (very good) gyms in Berlin and a lot will depend on where exactly you live. My favorite is Bright Site in Schöneberg which also happens to be my local.
There’s a sport flat rate here which means you can go to all the gyms as well as loads of other sports. This costs 59 Euros a month and can be cancelled with just one month’s notice at any point. Just search for urban sports club berlin. If you do end up going for this option, you can email me and I can give you a code and this way we both get a month free of charge.
If you have any other questions about bouldering or climbing in Berlin, feel free to send me a msg/email.
Mike