This work leverages globally consistent data on parks from Google Maps, in combination with the computational power of Google Maps Directions API to quantify accessibility to parks across nearly 500 metropolitan areas in six countries: Estonia, France, Greece, Mexico, Sweden, and the United States. We combined high resolution population data from Worldpop with parks data and navigation estimates to measure: (1) Fraction of the population with access to parks within a 10-minute walk; and (2) the median walking time to the closest park. We find large differences in access to parks between countries, as well as large variability across cities and their respective commuting zones. To demonstrate how this framework can support cross country comparisons and efforts to track progress towards SDG11, we assessed access to parks by income group in selected countries, finding that the median walking time to a park is shorter for residents of low income neighbourhoods both in French and American metropolitan areas.