Colletes halophilus is a striking short-tongued mining bee[3] which has its thorax coated with reddish brown hair, and a black abdomen with contrasting pale whitish to yellow bands.

The nesting aggregations are situated at the inland edges of the saltmarshes out of the reach of all but the highest tides and close to sources of food.

The sites chosen for nests are usually bare sandy soils, which are warmer than the surrounding vegetated areas due to exposure to the sun, often placed on south-facing slopes.

The nesting sites are located at the edge of saltmarshes and may occasionally be flooded by the highest spring tides; bees have been observed emerging from recently submerged mud.

Each nest consists of a short, curved burrow which terminates in a cluster of around half a dozen cells which radiate around the end of the shaft.

The bees feed on a limited range of plants, mostly in the Asteraceae, including weld (Reseda luteola),[6] but sea aster is especially important.

Both males and females need to feed on pollen to power their flight, and it is important that the nesting aggregations are located close to sources of food.