Longtime gym climber here. Travel a lot for work. So... I have sampled a few dozen climbing gyms…read morearound the world. This review is based on one visit on a wednesday evening in June 2017.
Boulderwelt is awesome. Huge space-- probably the largest bouldering space I have seen anywhere. There are so many walls. The routes are not even jammed into the space, and the gym still felt like there was plenty of room, not crowded at all.
The most distinctive thing about the gym was the route setting. Routes here uniformly reward patience and balance and slow-twitch technical skill. There are not so many dynos or superhero moves like my local gym. It took me half the session but once I got used to the style and knew what to expect, I started flashing half the routes I tried. Overall I really enjoyed climbing here.
-1 star for a couple of things... it's 90 minutes walk from the center city, and 15 minutes walk from the nearest train station. It's worth the trip, but it is a long trip. Also, the walls and holds are very rough; they need sanding; wear long sleeves and long pants or else be prepared to leave some skin on the wall. And as big as the gym is, there was only one staff member handling the desk. He did his best but the place seemed understaffed to me.
Will definitely return next time I am in frankfurt. Thank you Boulderwelt!