• Bouldering license for under-12s, a course taken with a parent, needed before kids can climb the main mats outside classes
• Two kids per adult at most, and the adult must supervise actively, paying regular entry even when not climbing
• Quietest on weekday daytimes and weekend mornings or evenings; weekday evenings from 6pm and weekend afternoons are busiest

Ostbloc is a bouldering hall of over 1,000 square meters by the Rummelsburger Bucht, open since 2010. Bouldering means climbing at jump-off height with no ropes or harness, over thick mats, at every difficulty level.

Kids under 8 have their own Kinderland area. Under-12s who want the main mats first take the Boulderführerschein, a course done with a parent that covers the hall rules.