Beach voles are typically much larger than meadow voles. On average, male beach voles are 192.9 mm long, ranging between 169 and 215 mm; with the tail making up approximately one-fourth of the total length. Generally, females are smaller, with an average length of 181.2 mm, ranging between 165 and 201 mm. The weight of a beach vole ranges between 29 and 79 g, proportional to age, with females weighing less than males. Compared to meadow voles, beach voles exhibit a lower metabolism, and their coat is made up of more guard hairs and fewer underhairs. A white blaze can often be found on the chin or forehead.

These voles dominate an open habitat of poison ivy and beach grass. Swaths of bare sand and saltwater marsh can be found on the island, but the voles tend to avoid these areas. They may burrow in loose sand or loose soil under or near any of their shelters. They feed on beach grass stalks, leaves, seeds, and insect adults and larvae. Their predators include birds of prey such as the short-eared owl and the northern harrier. The young beach voles are born in the burrow nests or underneath fragments of wreckage or at the base of goldenrod.