Research Note: Residential distance and recreational visits to coastal and inland blue spaces in eighteen countries

•Home distances to coasts, lakes, and rivers were exponentially related to visits.•We develop and demonstrate the utility of resultant general-purpose categorisations.•≤1km, >1–5 km, >5–25 km, >25–50 km, and >50 km suitable for coastal distance.•≤1km, >1–5 km, >5km suitable for lake distance.•≤1km, >1–2.5 km, >2.5 km adequate for river distance. Varied categorisations of residential distance to bluespace in population health studies make comparisons difficult. Using survey data from eighteen countries, we modelled relationships between residential distance to blue spaces (coasts, lakes, and rivers), and self-reported recreational visits to these environments at least weekly, with penalised regression splines. We observed exponential declines in visit probability with increasing distance to all three environments and demonstrated the utility of derived categorisations. These categories may be broadly applicable in future research where the assumed underlying mechanism between residential distance to a blue space and a health outcome is direct recreational contact.