zellkonverter is a Bioconductor R package that provides methods to convert between Python AnnData objects and SingleCellExperiment objects (https://bioconductor.org/packages/zellkonveter/). These are primarily intended for use by downstream Bioconductor packages that wrap Python methods for single-cell data analysis. It also includes functions to read and write H5AD files used for saving AnnData objects to disk.