Use of preposition to demonstrate direction

"Someone saw me coming in the opposite direction / someone saw me coming to the opposite direction"

In the first example, "in" means "observed direction from their position". In the second example, "to" is unclear as to meaning. Does it mean "going to" or "coming/going toward" something other than the observer?

Depending on intended meaning/description, either might be correct. However, in general the direction one travels relevant to an observer is described with the preposition "in" or in this example perhaps "from".