"האמבטיה שלהם מספיק גדולה בשביל להכיל פיל."
Translation:Their bath is big enough to contain an elephant.
I can see your version working well in writing, but I don't think anyone would drop the בשביל in informal spoken language.
Maybe the better translation would be, "...big enough for holding an elephant."
From an English perspective,it is not wrong, but I can't imagine using large instead of big in normal conversation. It just sounds unnatural in that sentence.