Ariadaeus is a small, bowl-shaped lunar impact crater on the western shores of Mare Tranquillitatis.

The crater is joined along the northeast rim by the slightly smaller Ariadaeus A, and the two form a double-crater.

[1] This crater marks the eastern extent of the rille designated Rima Ariadaeus.

This wide rille extends in a nearly straight line to the west-northwest, passing just to the north of the crater Silberschlag.

[1][2] By convention these features are identified on lunar maps by placing the letter on the side of the crater midpoint that is closest to Ariadaeus.