Very little, which can be its charm or its downfall. There are lots of trails to hike on around Karlskrona…none of them are challenging at all, so they are nice to do in large, mixed groups. You can also grill and swim in the summer, though the beaches are a bit gross due to the overgrowth of slimy green underwater plants due to the poisoning of the ocean. The shops close early (about 6 p.m.), and there is not much shopping to speak of…except for “nya skafferiet”...the “new pantry” delicatessen. They have tons of really great cheeses and meats. I would not recommend Karlshamn for more than a day…nothing to do there. The view is nice, though. However, if you want to have more things to do, I would say skip Blekinge and go see Stockholm or Gothenburg instead.