A novel soybean variety, designated XB40U10 is provided. Also provided are the seeds of soybean variety XB40U10, cells from soybean variety XB40U10, plants of soybean XB40U10, and plant parts of soybean variety XB40U10. Methods provided include producing a soybean plant by crossing soybean variety XB40U10 with another soybean plant, methods for introgressing a transgenic, mutant trait, and/or native trait into soybean variety XB40U10, methods for producing other soybean varieties or plant parts derived from soybean variety XB40U10. Soybean seed, cells, plants, germplasm, breeding lines, varieties, and plant parts produced by these methods and/or derived from soybean variety XB40U10 are further provided.
