Does a full bath have to have a bath tub?

Yes, a full bath typically includes a bathtub, but it can also refer to a bathroom that contains a combination of a bathtub and a shower. The standard definition of a full bath includes at least four components: a toilet, a sink, a bathtub, and a shower. However, in some contexts, a bathroom with just a shower in place of a bathtub may also be considered a full bath, especially in modern designs.