Luckse Sound is a sound in Casco Bay, Maine, United States.

Located between Long Island and Cliff Island,[1] it is one of the deepest channels which separate inner Casco Bay from its outlying waters in the Gulf of Maine, after Portland Channel, Hussey Sound and Broad Sound.

[2] Ships were torpedoed in the sound during World War II.

[3][4] Today, the Casco Bay Mailboat passes through the sound.