The Karkinit Bay, or Gulf of Karkinit (Ukrainian: Каркінітська затока, variously transliterated from Russian and Ukrainian as Karkinite Bay, Karkinitsky Bay, Karkinitski Bay, etc.) is a bay of the Black Sea that separates the southwestern Crimean Peninsula from the mainland Ukraine. It was named after the early Greek settlement of Kerkinitis (Κερκινίτης) on the Crimean coast in place of modern Yevpatoria.
The northeastern tip of the Karkinitis Bay, by the Isthmus of Perekop, is known as the Perekop Bay or Gulf of Perekop.