A novel soybean cultivar, designated SO22218, is disclosed. The invention relates to the seeds of soybean cultivar SO22218, to the plants of soybean SO22218 and to methods for producing a soybean plant produced by crossing the cultivar SO22218 with itself or another soybean variety. The invention further relates to hybrid soybean seeds and plants produced by crossing the cultivar SO22218 with another soybean cultivar.