Late in 2020, two genetically-distinct clusters of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with mutations of biological concern were reported in the United Kingdom. Using a combination of data from routine surveillance, genomic sequencing and international travel we track the international dispersal of lineages B.1.1.7 and B.1.351 (variant 501Y-V2). Further, we have built a custom tracking website (cov-lineages.org/global_report.html) which is updated daily and will continue to include novel SARS-CoV-2 lineages of concern as they are detected.