A nice day trip from Solwezi is going swimming at Mutanda Falls. You can get to Mutanda Lodge (not Mutanda Nature Lodge), either by hitching out of Solwezi (best place to start is after Chowama market), or taking a taxi if you have money or can split it with people. At the Lodge there is a place to swim in the water, you’ll need to pay about 20kwa to be allowed to do so, or hang out in the nsakas by the water. Keep in mind that as rain season starts to pick up the water might be too strong to swim in. Rain season starts in October and goes until about April. I would think August/September would be the best time, although I went in April/May and it was pretty good. They also sell food at the lodge but I can’t attest to how good it is. Mutanda Falls isn’t very big compared to other falls in Zambia but its still a nice and relaxing outing nonetheless.
Mutanda Lodge is the yellow pin in the map below, the orange road going of the top of the picture goes to Solwezi.