These are small or medium-sized swallows, ranging from 11–17 cm in length. They are brown above and mainly white below, and all have a dark breast band.
These species are closely associated with water. They nest in tunnels usually excavated by the birds themselves in a natural sand bank or earth mound. They lay white eggs, which are incubated by both parents, in a nest of straw, grass, and feathers in a chamber at the end of the burrow. Some species breed colonially.
The cosmopolitan sand martin is almost completely migratory, breeding across temperate Eurasia and North America and wintering in the tropics. The other species are partial migrants or resident.
Riparia martins, like other swallows, take insects in flight over water, grassland, or other open country.