The Riama Island melomys was described from coastal Riama Island in Indonesia. The original account reports a group feeding on seeds around midday beneath coastal Casuarina trees.
The original description notes dark rings around the eyes, white lips, throat, chest, and abdomen, and buff-colored legs.
On Riama Island at sea level, a group was observed around midday feeding on seeds in leaf litter beneath shrubs under coastal Casuarina trees in open scrub.
An extinction-risk assessment has not been added yet.