A novel soybean variety, designated XBP31005 is provided. Also provided are the seeds of soybean variety XBP31005, cells from soybean variety XBP31005, plants of soybean XBP31005, and plant parts of soybean variety XBP31005. Methods provided include producing a soybean plant by crossing soybean variety XBP31005 with another soybean plant, methods for introgressing a transgenic, mutant trait, and/or native trait into soybean variety XBP31005, methods for producing other soybean varieties or plant parts derived from soybean variety XBP31005. Soybean seed, cells, plants, germplasm, breeding lines, varieties, and plant parts produced by these methods and/or derived from soybean variety XBP31005 are further provided.