Basidiomycete mycelia are ubiquitous in forest soils where they fulfil a range of key ecological functions. Population studies, based largely on basidiome collections, indicate that mycelia of many ectomycorrhizal and saprotrophic basidiomycetes can spread vegetatively for considerable distances through soil, but the extent to which these become physically or physiologically fragmented is unclear. This review considers aspects of the distribution, dynamics and translocatory activities of individual basidiomycete mycelia in forest soil, highlighting current gaps in our understanding and possible ways to address these.