Current Earth Observation applications heavily rely on analyses of dense intra-annual or inter-annual time series. State-of-the-art analysis workflows thus require mass processing of satellite data, with data volumes easily exceeding several terabytes, even for relatively small areas of interest. Cloud processing platforms such as Google EarthEngine (GEE) leverage accessibility to satellite image archives and facilitate time series analysis workflows. Instant visualization of time series data, though, is currently not implemented or requires coding customized scripts or applications. We here present the GEE Timeseries Explorer which allows instant access to any Earth Engine image collection from within QGIS. It seamlessly integrates the QGIS UI with a compact widget for visualizing time series from any GEE image collection graphically as an interactive plot, or spatially as images with customized band rendering. The GEE Timeseries Explorer offers flexible integration of any GEE image collection, such as the MODIS, Landsat, Sentinel-2AB, or Sentinel-1 product suites. Image collections can be modified in a collection editor widget to include, e.g., quality filtering, cloud- and cloud-shadow masking, or adding band indices or transformations. We added a set of pre-defined collections, including quality-filtered MODIS VI products, integrated and cloud-masked Landsat TM, ETM+, OLI, or cloud-masked Sentinel-2AB surface reflectance products. Users are encouraged to contribute to the plugin by sharing custom collections through the plugin repository or the plugin homepage.