Soybean variety XBP21005

A novel soybean variety, designated XBP21005 is provided. Also provided are the seeds of soybean variety XBP21005, cells from soybean variety XBP21005, plants of soybean XBP21005, and plant parts of soybean variety XBP21005. Methods provided include producing a soybean plant by crossing soybean variety XBP21005 with another soybean plant, methods for introgressing a transgenic trait, a mutant trait, and/or a native trait into soybean variety XBP21005, methods for producing other soybean varieties or plant parts derived from soybean variety XBP21005, and methods of characterizing soybean variety XBP21005. Soybean seed, cells, plants, germplasm, breeding lines, varieties, and plant parts produced by these methods and/or derived from soybean variety XBP21005 are further provided.