Yes, you can use soft pastels with watercolor! In fact, many artists enjoy using the two mediums together to create unique and beautiful works of art.
When using soft pastels with watercolor, it's important to keep a few things in mind. First, make sure your pastels are dry before applying them to wet paper. Second, use a light touch when applying the pastels - too much pressure will cause the colors to bleed and run. Finally, be sure to seal your finished painting with a fixative spray to prevent the pastels from smudging or running.
With a little practice, you'll be able to create stunning paintings by combining soft pastels and watercolor!